func_code_string: #include <bits/stdc++.h>   using namespace std;   const int mod = 1e9 + 7;   const int N = 55;   int n, m;   int f[N][N], g[N][N], h[N][N], F[N][N], inv[N];   inline long long qpow(long long a, long long b) {     long long res = 1;     for (; b; b >>= 1, a = a * a % mod)       if (b & 1) res = res * a % mod;     return res;   }   inline void add(int &x, int y) {     x += y;     if (x >= mod) x -= mod;   }   inline void dec(int &x, int y) {     x -= y;     if (x < 0) x += mod;   }   int main() {     cin >> n >> m;     for (int i = 1; i <= n + 1; i++) inv[i] = qpow(i, mod - 2);     f[0][1] = 1;     h[0][0] = 1;     for (int i = 1; i <= n; i++) {       for (int j = n + 1; j >= 1; j--)         F[i - 1][j] = (F[i - 1][j + 1] + f[i - 1][j]) % mod;       for (int j = n + 1; j >= 1; j--)         for (int k = 0; k < i; k++)           add(g[i][j], 1ll * F[k][j] * F[i - k - 1][j] % mod);       for (int j = 1; j <= n + 1; j++) dec(g[i][j], g[i][j + 1]);       for (int j = 1; j <= n + 1; j++)         for (int x = n; x >= 0; x--)           for (int y = n + 1; y >= 0; y--) {             int res = 0, c = 1;             for (int k = 0; k * i <= x && k * j <= y; k++) {               add(res, 1ll * h[x - k * i][y - k * j] * c % mod);               c = 1ll * c * (g[i][j] + k) % mod * inv[k + 1] % mod;             }             h[x][y] = res;           }       for (int j = 1; j <= n + 1; j++) f[i][j] = h[i][j - 1];     }     printf( %d , f[n][m]);     return 0;   }   