#include <bits/stdc++.h>
#define REP(i, a, n) for(ll i = ((ll) a); i < ((ll) n); i++)
#define MOD 1000000007LL
using namespace std;
typedef long long ll;

ll N, K, A[300];

int main(void) {
  cin >> N >> K;
  REP(i, 0, N) cin >> A[i];

  vector< vector<ll> > dp(N + 1, vector<ll>(K + 1, 0));
  dp[0][0] = 1;
  REP(i, 0, N) {
    vector<ll> sum(K + 2, 0);
    REP(j, 0, K + 1) sum[j + 1] = dp[i][j];
    REP(j, 0, K + 1) {
      sum[j + 1] += sum[j];
      sum[j + 1] %= MOD;
    }

    REP(j, 0, K + 1) {
      ll l = max(j - i, 0LL), r = j;
      dp[i + 1][j] += (sum[r + 1] - sum[l] + MOD) % MOD;
      dp[i + 1][j] %= MOD;
    }
  }

  ll ans = 0;
  REP(i, 0, K + 1) {
    ans += dp[N][i];
    ans %= MOD;
  }
  cout << ans << endl;
}