func_code_string: #include <bits/stdc++.h>   using namespace std;   int i, j, k, n, m, u, i1, i2, s;   long long f[60][60][2], C[60][60];   inline void M(int j, int k, long long A) {     A %= 1000000007;     f[i][j][k] = (f[i][j][k] + A) % 1000000007;   }   inline long long pow(long long x, long long y) {     long long an = 1;     for (; y; y >>= 1) {       if (y & 1) an = an * x % 1000000007;       x = x * x % 1000000007;     }     return an;   }   int main() {     scanf( %d%d , &n, &m);     for (i = 0; i <= n; i++) {       C[i][0] = 1;       for (j = 1; j <= i; j++)         C[i][j] = (C[i - 1][j] + C[i - 1][j - 1]) % 1000000007;     }     f[1][0][0] = 1;     long long P = pow(2, 1000000007 - 2);     for (i = 2; i <= n; i++) {       s = i == n ? 1 : i;       for (j = 0; j <= i - 1; j++) {         M(j + 1, 1, s * f[i - 1][j][0]);         M(j, 0, s * f[i - 1][j][1]);       }       for (j = 1; j + 1 < i; j++)         for (k = 0; k <= j; k++)           for (i1 = 0; i1 <= 1; i1++) {             int A = i - 1 - j;             for (u = 0; u <= A; u++)               for (i2 = 0; i2 <= 1; i2++) {                 long long B = f[j][k][i1] * C[i - 1][j] % 1000000007 *                               f[A][u][i2] % 1000000007 * s % 1000000007 * P %                               1000000007;                 int C = k + u + (!i1 || !i2), D = !(i1 && i2);                 M(C, D, B);               }           }     }     printf( %I64d n , (f[n][m][0] + f[n][m][1]) % 1000000007);     return 0;   }   