#include <iostream>
using namespace std;

const int N = 101, K = 1e5 + 1, MOD = 1e9 + 7;

int n, k, val[N], pos[K];

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  
  cin >> n >> k;
  
  for(int i = 0; i < n; i++)
    cin >> val[i];
  
  pos[0] = 1;
  for(int i = 0; i < n; i++) {
    int d = k, sum = 0;
    for(int f = k; f > -1; f--) {
      sum = (sum - pos[f] + MOD) % MOD;
      while(d > -1 && f - d <= val[i])
        sum = (sum + pos[d--]) % MOD;
      pos[f] = (pos[f] + sum) % MOD;
    }
  }
  cout << pos[k];
}