#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#ifdef ONLINE_JUDGE
#define getchar getchar_unlocked
#endif
namespace FastIO
{
    char write_cache[40];
    template <class T>
    inline const T read() noexcept
    {
        T x(0);
        char ch(getchar());
        bool f(0);
        while (ch < '0' || ch > '9')
            f ^= ch == '-', ch = getchar();
        while (ch >= '0' && ch <= '9')
            x = (x << 1) + (x << 3) + (ch ^ 48), ch = getchar();
        return f ? -x : x;
    }
    template <class T>
    inline const void read(T &x) noexcept
    {
        x = 0;
        char ch(getchar());
        bool f(0);
        while (ch < '0' || ch > '9')
            f ^= ch == '-', ch = getchar();
        while (ch >= '0' && ch <= '9')
            x = (x << 1) + (x << 3) + (ch ^ 48), ch = getchar();
        x = f ? -x : x;
    }
    template <class T, class... P>
    inline const void read(T &x, P &...ark) noexcept
    {
        x = 0;
        char ch(getchar());
        bool f(0);
        while (ch < '0' || ch > '9')
            f ^= ch == '-', ch = getchar();
        while (ch >= '0' && ch <= '9')
            x = (x << 1) + (x << 3) + (ch ^ 48), ch = getchar();
        x = f ? -x : x;
        read(ark...);
    }
    template <class T>
    inline const void readu(T &x) noexcept
    {
        x = 0;
        char ch(getchar());
        bool f(0);
        while (ch < '0' || ch > '9')
            ch = getchar();
        while (ch >= '0' && ch <= '9')
            x = (x << 1) + (x << 3) + (ch ^ 48), ch = getchar();
    }
    template <class T>
    inline const T readu() noexcept
    {
        T x(0);
        char ch(getchar());
        bool f(0);
        while (ch < '0' || ch > '9')
            ch = getchar();
        while (ch >= '0' && ch <= '9')
            x = (x << 1) + (x << 3) + (ch ^ 48), ch = getchar();
        return x;
    }
    template <class T, class... P>
    inline const void readu(T &x, P &...ark) noexcept
    {
        x = 0;
        char ch(getchar());
        bool f(0);
        while (ch < '0' || ch > '9')
            ch = getchar();
        while (ch >= '0' && ch <= '9')
            x = (x << 1) + (x << 3) + (ch ^ 48), ch = getchar();
        readu(ark...);
    }
    template <class T>
    inline const void readArr(T *begin, T *end) noexcept
    {
        while (begin < end)
        {
            *begin = 0;
            char ch(getchar());
            bool f(0);
            while (ch < '0' || ch > '9')
                f ^= ch == '-', ch = getchar();
            while (ch >= '0' && ch <= '9')
                *begin = (*begin << 1) + (*begin << 3) + (ch ^ 48), ch = getchar();
            *begin = f ? -*begin : *begin;
        }
    }
    template <class T>
    inline const void readArr(T *begin, int cnt) noexcept
    {
        while (cnt--)
        {
            read(*begin);
            ++begin;
        }
    }
    template <class T>
    inline const void write(T x) noexcept
    {
        if (x < 0)
            putchar('-'), x = -x;
        int cnt = 0;
        while (x)
            write_cache[cnt++] = x % 10 ^ 48, x /= 10;
        if (!cnt)
            putchar('0');
        else
            while (cnt--)
                putchar(write_cache[cnt]);
    }
    template <char end = ' ', class T, class... ARK>
    inline const void write(T &x, ARK &...ark) noexcept
    {
        write(x);
        putchar(end);
        write(ark...);
    }
    template <char end = '\n', class T>
    inline const void println(T x) noexcept
    {
        if (x < 0)
            putchar('-'), x = -x;
        int cnt = 0;
        while (x)
            write_cache[cnt++] = x % 10 ^ 48, x /= 10;
        if (!cnt)
            putchar('0');
        else
            while (cnt--)
                putchar(write_cache[cnt]);
        putchar(end);
    }
    template <char sep = ' ', char endl = '\n', class T>
    inline const void writeArr(T *begin, T *end) noexcept
    {
        while (begin < end)
            write(*begin), putchar(sep), ++begin;
        putchar(endl);
    }
    template <char sep = ' ', char end = '\n', class T>
    inline const void writeArr(T *arr, int cnt)
    {
        while (cnt--)
        {
            write(*arr);
            putchar(sep);
            ++arr;
        }
        putchar(end);
    }
}

#define maxn 5001
int n, m, k, front, FRONT, back, BACK, ans;
int a[maxn][maxn], q[maxn], Q[maxn];
int x[maxn][maxn], X[maxn][maxn];
int y[maxn][maxn], Y[maxn][maxn];
int main()
{
    FastIO::read(n, m, k);
    for (int i = 1; i <= n; ++i)
        FastIO::readArr(a[i], m);
    for (int i = 1; i <= n; ++i)
    {
        FRONT = BACK = front = back = Q[1] = q[1] = 1;
        for (int j = 2; j <= m; ++j)
        {
            while (a[i][j] >= a[i][Q[BACK]] && FRONT <= BACK)
                --BACK;
            while (a[i][j] <= a[i][q[back]] && front <= back)
                --back;
            ++BACK, ++back, Q[BACK] = j, q[back] = j;
            while (j - Q[FRONT] >= k)
                ++FRONT;
            while (j - q[front] >= k)
                ++front;
            if (j >= k)
                X[i][j - k + 1] = a[i][Q[FRONT]], x[i][j - k + 1] = a[i][q[front]];
        }
    }
    for (int i = 1; i <= m - k + 1; ++i)
    {
        FRONT = BACK = front = back = Q[1] = q[1] = 1;
        for (int j = 2; j <= n; ++j)
        {
            while (X[j][i] >= X[Q[BACK]][i] && FRONT <= BACK)
                --BACK;
            while (x[j][i] <= x[q[back]][i] && front <= back)
                --back;
            ++BACK, ++back, Q[BACK] = j, q[back] = j;
            while (j - Q[FRONT] >= k)
                ++FRONT;
            while (j - q[front] >= k)
                ++front;
            if (j >= k)
                Y[j - k + 1][i] = X[Q[FRONT]][i], y[j - k + 1][i] = x[q[front]][i];
        }
    }
    ans = INT_MAX;
    for (int i = 1; i <= n - k + 1; ++i)
        for (int j = 1; j <= m - k + 1; ++j)
            ans = min(ans, Y[i][j] - y[i][j]);
    FastIO::println(ans);
    return 0;
}