func_code_string: #include <bits/stdc++.h>   using namespace std;   const int PI = acos(-1);   const int MAXN = 1e6;   unsigned long long comb(unsigned long long n, unsigned long long k) {     if (k > n) return 0;     unsigned long long u = 1;     for (unsigned long long i = 1; i <= k; i++) {       u *= n--;       u /= i;     }     return u;   }   int main() {     unsigned long long n, m, t;     while (cin >> n >> m >> t) {       unsigned long long ans = 0;       for (unsigned long long boys = 4; boys <= n; boys++) {         unsigned long long girls = t - boys;         if (girls > m) continue;         if (t < 1 + boys) break;         ans += comb(n, boys) * comb(m, girls);       }       cout << ans << endl;     }     return 0;   }   