func_code_string: #include <bits/stdc++.h>   using namespace std;   const long long N = 1e3 + 5;   long long C[N][5], dif_fact[5];   void calc() {     for (long long i = 0; i < N; i++) {       for (long long j = 0; j <= min(i, 4LL); j++) {         if (j == 0 || j == i) {           C[i][j] = 1;         } else {           C[i][j] = C[i - 1][j - 1] + C[i - 1][j];         }       }     }     dif_fact[1] = 0;     dif_fact[2] = 1;     dif_fact[3] = 2;     dif_fact[4] = 9;   }   signed main() {     ios_base ::sync_with_stdio(0);     cin.tie(0);     cout.tie(0);     ;     calc();     long long n, k;     cin >> n >> k;     long long ans = 1;     for (long long i = 2; i <= k; i++) {       long long curr = C[n][i] * dif_fact[i];       ans += curr;     }     cout << ans;   }   