#include <iostream>
#include <vector>

using namespace std;

const int mod = 1000000007;

int main() {
    int N, K;
    cin >> N >> K;

    vector<long long int> A(N);
    for (int i = 0; i < N; ++i) {
        cin >> A[i];
    }

    vector<long long int> DP = {1, 1};

    for (int i = 3; i <= N; ++i) {
        vector<long long int> NDP(i * (i - 1) / 2 + 1, 0);

        for (int j = 0; j < i; ++j) {
            for (int k = 0; k < DP.size(); ++k) {
                NDP[j + k] = (NDP[j + k] + DP[k]) % mod;
            }
        }

        DP = NDP;
    }

    int result = 0;
    for (int i = 0; i <= K && i < DP.size(); ++i) {
        result = (result + DP[i]) % mod;
    }

    cout << result << endl;

    return 0;
}