#include <bits/stdc++.h>
using namespace std;
const long long p = 1e9 + 7;
long long g[60][60][2], C[60][60];
int main() {
  for (int i = 0; i <= 50; i++) {
    C[i][0] = 1;
    for (int j = 1; j <= i; j++) C[i][j] = (C[i - 1][j - 1] + C[i - 1][j]) % p;
  }
  int n0, k0;
  scanf("%d%d", &n0, &k0);
  g[0][0][1] = g[1][0][0] = 1;
  for (int n = 2; n <= n0; n++) {
    for (int k = 0; 2 * k <= (2 * k0 < n ? 2 * k0 : n); k++) {
      for (int nl = 0; 2 * nl < n; nl++) {
        for (int kl = 0; 2 * kl <= (2 * k < nl ? 2 * k : nl); kl++) {
          int nr = n - nl - 1, kr = k - kl;
          long long mul = C[n - 1][nl] * (nl > 1 ? nl : 1) * nr % p;
          if (nl == nr) mul = mul * (p + 1) / 2 % p;
          g[n][k][0] = (g[n][k][0] + g[nl][kl][1] * g[nr][kr][1] % p * mul) % p;
          if (kr--) {
            g[n][k][1] =
                (g[n][k][1] + g[nl][kl][0] * g[nr][kr][0] % p * mul) % p;
            g[n][k][1] =
                (g[n][k][1] + g[nl][kl][0] * g[nr][kr][1] % p * mul) % p;
            g[n][k][1] =
                (g[n][k][1] + g[nl][kl][1] * g[nr][kr][0] % p * mul) % p;
          }
        }
      }
    }
  }
  printf("%lld\n", (g[n0][k0][0] + g[n0][k0][1]) % p);
  return 0;
}
