func_code_string: #include <bits/stdc++.h>   using namespace std;   const int MAXN = 4000 + 10, MOD = (int)1e9 + 9;   int n, m, b, w, f[MAXN][MAXN];   int main() {     cin >> n >> w >> b;     m = max(b, w);     f[0][0] = 1;     for (int i = 1; i <= m; ++i) {       for (int j = 1; j <= i; ++j)         f[i][j] = ((long long)f[i - 1][j] * (j + i - 1) +                    (long long)f[i - 1][j - 1] * j) %                   MOD;     }     int Tohka = 0;     for (int i = 1; i <= min(b, n - 2); ++i)       Tohka = ((long long)Tohka +                (long long)f[w][n - i] * f[b][i] % MOD * (n - i - 1)) %               MOD;     cout << Tohka << endl;     fclose(stdin);     fclose(stdout);     return 0;   }   