#include <bits/stdc++.h>
using namespace std;
const long long mod = 1000000007;
const int Maxn = 50 + 10;
int n, k, cnt;
long long f[Maxn][Maxn][2], c[Maxn][Maxn], sum, ans;
void assign() {
  freopen("Ksenia and Combinatorics.in", "r", stdin);
  freopen("Ksenia and Combinatorics.out", "w", stdout);
}
void close() {
  fclose(stdin);
  fclose(stdout);
}
void init() {
  scanf("%d%d\n", &n, &k);
  c[0][0] = 1;
  for (int i = 1; i <= n; ++i) {
    c[i][0] = 1;
    for (int j = 1; j <= i; ++j)
      c[i][j] = (c[i - 1][j] + c[i - 1][j - 1]) % mod;
  }
  f[1][0][0] = 1;
  f[0][0][1] = 1;
  for (int i = 2; i <= n; ++i)
    for (int l = 0, r = i - 1; l <= r; ++l, --r) {
      sum = (l != r) ? c[i - 1][l] : c[i - 2][l - 1];
      if (i != n) sum = (sum * i) % mod;
      for (int k1 = 0; 2 * k1 <= l; ++k1)
        for (int k2 = 0; 2 * k2 <= r; ++k2)
          for (int c1 = 0; c1 <= 1; ++c1)
            for (int c2 = 0; c2 <= 1; ++c2)
              if (f[l][k1][c1] && f[r][k2][c2]) {
                cnt = !(c1 && c2);
                ans = ((f[l][k1][c1] * f[r][k2][c2]) % mod * sum) % mod;
                (f[i][k1 + k2 + cnt][cnt] += ans) %= mod;
              }
    }
  cout << (f[n][k][0] + f[n][k][1]) % mod << endl;
}
int main() {
  init();
  return 0;
}
