#include <bits/stdc++.h>   using namespace std;   int sti(const string &s) {     int x;     stringstream ss(s);     ss >> x;     return x;   }   string its(const int &x) {     string s;     stringstream ss(s);     ss << x;     s = ss.str();   }   void sscan(string &str) {     str =   ;     char str_c;     scanf( %c , &str_c);     while (!(str_c ==   n  || str_c ==    )) {       str += str_c;       scanf( %c , &str_c);     }   }   void sprint(const string &str) {     int length = str.length();     for (int i = 0; i < length; ++i) printf( %c , str[i]);   }   uint64_t fact(int x) {     if (x < 2) return 1;     return fact(x - 1) * x;   }   uint64_t C(int x, int y) {     uint64_t c = 1;     for (int i = 0; i < y; ++i) {       c *= x - i;       c /= i + 1;     }     return c;   }   int main() {     int n, m, t;     scanf( %d %d %d , &n, &m, &t);     uint64_t res = 0;     for (int i = 4; i <= n && i < t; ++i) {       if (t - i > m) continue;       res += C(n, i) * C(m, t - i);     }     printf( %I64u , res);     return 0;   }   