func_code_string: #include <bits/stdc++.h>   using namespace std;   int n, m1, m2;   long long C[4005][4005], f[4005], ret;   long long MOD = 1000000009;   int main() {     for (int i = 0; i <= 4000; i++) {       C[i][0] = C[i][i] = 1;       for (int j = 1; j <= i; j++)         C[i][j] = (C[i - 1][j - 1] + C[i - 1][j]) % MOD;     }     f[0] = 1;     for (int i = (1); i <= (4000); i++) f[i] = (f[i - 1] * i) % MOD;     ret = 0;     scanf( %d%d%d , &n, &m1, &m2);     for (int i = (1); i <= (m1); i++)       for (int j = (1); j <= (m2); j++)         if (i + j < n && n - j <= m1) {           ret += C[m2 - 1][j - 1] * f[m2] % MOD * C[m1 - 1][n - j - 1] % MOD *                  f[m1] % MOD;           ret %= MOD;         }     printf( %d n , (int)ret);     return 0;   }   