#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
using namespace std;

int N, K;

long dp[300][90000];

long array_patterns(int now_array_size, int now_inversion_number){
    if(now_array_size == N){
        return now_inversion_number <= K;
    }else if(dp[now_array_size][now_inversion_number] != -1){
        return dp[now_array_size][now_inversion_number];
    }else{
        long ans = 0;
        for(int i = 0; i <= now_array_size; i++){
            ans += array_patterns(now_array_size + 1, now_inversion_number + i);
            ans %= long(1e9 + 7);
        }
        return dp[now_array_size][now_inversion_number] = ans;
    }
}

int main(){
    cin >> N >> K;
    for(int i = 0; i < 300; i++){
        for(int j = 0; j < 90000; j++){
            dp[i][j] = -1;
        }
    }
    cout << array_patterns(0, 0) << endl;
}