#include <bits/stdc++.h>
using namespace std;
const long long INF = 1e18;
const int mod = 1000000007;
struct mint {
  long long x;
  mint(long long x = 0) : x((x % mod + mod) % mod) {}
  mint operator-() const { return mint(-x); }
  mint& operator+=(const mint a) {
    if ((x += a.x) >= mod) x -= mod;
    return *this;
  }
  mint& operator-=(const mint a) {
    if ((x += mod - a.x) >= mod) x -= mod;
    return *this;
  }
  mint& operator*=(const mint a) {
    (x *= a.x) %= mod;
    return *this;
  }
  mint operator+(const mint a) const { return mint(*this) += a; }
  mint operator-(const mint a) const { return mint(*this) -= a; }
  mint operator*(const mint a) const { return mint(*this) *= a; }
  mint pow(long long t) const {
    if (!t) return 1;
    mint a = pow(t >> 1);
    a *= a;
    if (t & 1) a *= *this;
    return a;
  }
  mint inv() const { return pow(mod - 2); }
  mint& operator/=(const mint a) { return *this *= a.inv(); }
  mint operator/(const mint a) const { return mint(*this) /= a; }
};
istream& operator>>(istream& is, const mint& a) { return is >> a.x; }
ostream& operator<<(ostream& os, const mint& a) { return os << a.x; }
mint dp[105][100005];
int main() {
  long long n, k;
  cin >> n >> k;
  vector<long long> a(n);
  for (long long i = 0; i < n; ++i) cin >> a[i];
  dp[0][0] = 1;
  for (long long i = 0; i < n; ++i) {
    vector<mint> v(k + 1);
    v[0] = 0;
    for (long long j = 0; j < k + 1; ++j) {
      v[j + 1] = v[j] + dp[i][j];
    }
    for (long long j = 0; j < k + 1; ++j) {
      if ((j - a[i]) < 0)
        dp[i + 1][j] = v[j + 1];
      else
        dp[i + 1][j] = v[j + 1] - v[j - a[i]];
    }
  }
  cout << dp[n][k] << endl;
}
