#include <bits/stdc++.h>
using namespace std;
long long dp[60][60][2];
long long C[60][60];
void update(long long &a, long long b) { a = (a + b) % 1000000007; }
int main() {
  long long n, k;
  scanf("%lld%lld", &n, &k);
  if (k * 2 > n) {
    printf("0");
    return 0;
  }
  for (long long i = 0; i <= n; i++) C[i][0] = 1;
  for (long long i = 1; i <= n; i++)
    for (long long j = 1; j <= i; j++)
      C[i][j] = (C[i - 1][j - 1] + C[i - 1][j]) % 1000000007;
  dp[1][0][0] = dp[0][0][1] = 1;
  for (long long siz = 2; siz <= n; siz++)
    for (long long mac = 1; mac <= k; mac++) {
      for (long long ls = 0, rs = siz - 1; ls <= rs; ls++, rs--) {
        for (long long lm = 0, rm = mac; lm <= mac; lm++, rm--) {
          if (lm * 2 > ls || rm * 2 > rs) continue;
          long long tmp = (ls == rs ? C[siz - 2][ls - 1] : C[siz - 1][ls]) *
                          (siz == n ? 1 : siz) % 1000000007;
          update(dp[siz][mac][0],
                 dp[ls][lm][1] * dp[rs][rm][1] % 1000000007 * tmp % 1000000007);
        }
      }
      for (long long ls = 0, rs = siz - 1; ls <= rs; ls++, rs--) {
        for (long long lm = 0, rm = mac - 1; lm < mac; lm++, rm--) {
          if (lm * 2 > ls || rm * 2 > rs) continue;
          long long tmp = (ls == rs ? C[siz - 2][ls - 1] : C[siz - 1][ls]) *
                          (siz == n ? 1 : siz) % 1000000007;
          update(dp[siz][mac][1],
                 dp[ls][lm][1] * dp[rs][rm][0] % 1000000007 * tmp % 1000000007);
          update(dp[siz][mac][1],
                 dp[ls][lm][0] * dp[rs][rm][1] % 1000000007 * tmp % 1000000007);
          update(dp[siz][mac][1],
                 dp[ls][lm][0] * dp[rs][rm][0] % 1000000007 * tmp % 1000000007);
        }
      }
    }
  printf("%lld", (dp[n][k][0] + dp[n][k][1]) % 1000000007);
  return 0;
}
