func_code_string: #include <bits/stdc++.h>   using namespace std;   long long A[1000000];   long long ncr(int n, int k) {     long long ans = 1;     k = k > n - k ? n - k : k;     int j = 1;     for (; j <= k; j++, n--) {       if (n % j == 0) {         ans *= n / j;       } else if (ans % j == 0) {         ans = ans / j * n;       } else {         ans = (ans * n) / j;       }     }     return ans;   }   int main() {     ios::sync_with_stdio(false);     long long n, m, t;     cin >> n >> m >> t;     long long sum = 0;     for (long long i = 4; i <= n; i++)       for (long long j = 1; j <= m; j++)         if (i + j == t) sum += ncr(n, i) * ncr(m, j);     cout << sum << endl;     return 0;   }   