#include <cstdio>
#include <cstring>
#include <string>
#include <iostream>
#include <cmath>
#include <bitset>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <algorithm>
using namespace std;
typedef long long int ll;
typedef pair<int, int> P;
const ll MOD=1e9+7;
int main()
{
	int n, k;
  cin>>n>>k;
  ll dp[301][45001]={};
  dp[1][0]=1;
  for(int i=1; i<n; i++){
    for(int j=0; j<=i; j++){
      for(int l=0; l<=i*(i-1)/2; l++){
        dp[i+1][j+l]+=dp[i][l];
        dp[i+1][j+l]%=MOD;
      }
    }
  }
  ll ans=0;
  for(int i=0; i<=k; i++){
    ans+=dp[n][i];
    ans%=MOD;
  }
  cout<<ans<<endl;
	return 0;
}