func_code_string: #include <bits/stdc++.h>   using namespace std;   long long n, ans = 1;   long long C(long long m, long long n) {     long long p = 1;     for (long long i = 1; i <= n; i++) p *= i;     for (long long i = 1; i <= m; i++) p /= i;     for (long long i = 1; i <= n - m; i++) p /= i;     return p;   }   signed main() {     cin >> n;     for (long long i = 1; i <= n / 2 - 1; i++) ans *= i;     ans *= ans;     ans *= C(n / 2, n);     ans /= 2;     cout << ans;     return 0;   }   