func_code_string: #include <bits/stdc++.h>   using namespace std;   const int MOD = 1e9 + 7;   const int N = 2222;   int n, K;   long long sum[N][N], tail[N], f[N][N];   char s[N];   long long work() {     long long ret = 0;     tail[n + 1] = 1;     for (int i = n; i >= 1; i--) tail[i] = tail[i + 1] * (s[i] -  a  + 1) % MOD;     if (K == 0) return tail[1];     f[0][0] = 1;     sum[0][0] = 1;     for (int i = 1; i <= n; i++) {       int dt = n - i + 1;       for (int j = 0; j <= K; j++) {         for (int k = i - 1; k >= 0 && (i - k) * dt <= j; k--) {           f[i][j] = (f[i][j] + f[k][j - (i - k) * dt]) % MOD;         }         f[i][j] = f[i][j] * ( z  - s[i]) % MOD;       }       for (int j = 0; j <= K; j++) {         f[i][j] = (f[i][j] + sum[i - 1][j] * (s[i] -  a ) % MOD) % MOD;         sum[i][j] = (sum[i - 1][j] + f[i][j]) % MOD;       }     }     ret = sum[n][K];     return ret;   }   int main() {     scanf( %d%d%s , &n, &K, s + 1);     printf( %I64d n , work());     return 0;   }   