#include <bits/stdc++.h>

using namespace std;

#define int long long
#define fir first
#define sec second
#define mkp make_pair 
#define pb push_back
#define lep( i, l, r ) for ( int i = ( l ); i <= ( r ); ++ i )
#define rep( i, r, l ) for ( int i = ( r ); i >= ( l ); -- i )

typedef long long ll;
typedef long double ld;
typedef pair < int, int > pii;

char _c; bool _f; template < class type > inline void read ( type &x ) {
	_f = 0, x = 0;
	while ( _c = getchar (), !isdigit ( _c ) ) if ( _c == '-' ) _f = 1;
	while ( isdigit ( _c ) ) x = x * 10 + _c - '0', _c = getchar (); if ( _f ) { x = -x; }
}

template < class type > inline void chkmin ( type &x, type y ) { x = ( x <= y ? x : y ); }
template < class type > inline void chkmax ( type &x, type y ) { x = ( x >= y ? x : y ); }

const int N = 5005;

int n, m, k, ans = 1e18;
int a[N][N], mini[N][N], maxi[N][N], tmp[N], tmp_maxi[N], tmp_mini[N];
int q[N];

void help ( int n, int a[], int res[], int id ) {
  int head = 0, tail = -1;
  for ( int i = 1; i <= n; i ++ ) {
    while ( head <= tail && q[head] < i - k + 1 ) {
      head ++;
    }
    while ( head <= tail && ( !id ? a[q[tail]] <= a[i] : a[q[tail]] >= a[i] ) ) {
      tail --;
    }
    q[++ tail] = i;
    res[i] = a[q[head]];
  }
}

void Solve () {
  ios :: sync_with_stdio ( false );
  cin.tie ( 0 ), cout.tie ( 0 );
  cin >> n >> m >> k;
  for ( int i = 1; i <= n; i ++ ) {
    for ( int j = 1; j <= m; j ++ ) {
      cin >> a[i][j];
    }
    help ( m, a[i], maxi[i], 0 );
    help ( m, a[i], mini[i], 1 );
  }
  for ( int i = k; i <= m; i ++ ) {
    for ( int j = 1; j <= n; j ++ ) {
      tmp[j] = maxi[j][i];
    }
    help ( n, tmp, tmp_maxi, 0 );
    for ( int j = 1; j <= n; j ++ ) {
      tmp[j] = mini[j][i];
    }
    help ( n, tmp, tmp_mini, 1 );
    for ( int j = k; j <= n; j ++ ) {
      ans = min ( ans, tmp_maxi[j] - tmp_mini[j] );
    }
  }
  cout << ans;
}

signed main () {
#ifdef judge
  freopen ( "Code.in", "r", stdin );
  freopen ( "Code.out", "w", stdout );
  freopen ( "Code.err", "w", stderr );
#endif
  Solve ();
	return 0;
}