func_code_string: #include <bits/stdc++.h>   using namespace std;   long long calc(long long n, long long k) {     long long a = 1, b = 1, c;     for (long long i = 1; i <= k; i++) a = a * (n - i + 1), b = b * i;     if (k == 4)       c = 9;     else if (k == 3)       c = 2;     else if (k == 2)       c = 1;     else       c = 0;     return c * a / b;   }   int main() {     long long n, k;     cin >> n >> k;     long long res = 0;     while (k) res += calc(n, k--);     cout << res + 1;     return 0;   }   