#include <iostream>
#include <vector>
#include <string>
#include <algorithm>

using namespace std;

int gcd(int a, int b) {
    return b == 0 ? a : gcd(b, a % b);
}

int main() {
    int n;
    cin >> n;

    vector<int> dp(n + 2, 0);
    dp[n] = 1; 

    for (int i = n - 1; i >= 1; --i) {
        dp[i] = dp[i + 1] * (i + 1) / (2 * (i + 1) - 1);
    }

    int numerator = dp[1];
    int denominator = 1; 


    int common_divisor = gcd(numerator, denominator);
    numerator /= common_divisor;
    denominator /= common_divisor;


    cout << numerator << "/" << denominator << endl;

    return 0;
}