#include <bits/stdc++.h>
using namespace std;
const long long MOD = 1000000007;
const long long MAX = 100005;
const long double PI = 3.14159265359;
const long double G = 9.807;
const long long INF = 1e18;
const long double EPS = 1e-6;
long long gcd(long long a, long long b) { return b ? gcd(b, a % b) : a; }
bool isprime(long long a) {
  if (a == 2) return 1;
  if (!(a & 1)) return 0;
  for (long long i = 3; i * i <= a; i += 2)
    if (a % i == 0) return 0;
  return 1;
}
long long mpow(long long base, long long exponent, long long modulus) {
  if (modulus == 1) return 0;
  long long result = 1;
  base = base % modulus;
  while (exponent) {
    if (exponent % 2 == 1) result = (result * base) % modulus;
    exponent = exponent >> 1;
    base = (base * base) % modulus;
  }
  return result;
}
long long minv(long long a, long long mod) {
  long long _gcd = gcd(a, mod);
  assert(_gcd == 1);
  return mpow(a, mod - 2, mod);
}
long long n, K;
long long a[105];
long long dp[105][100001];
long long pre[100001];
int main() {
  ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  cin >> n >> K;
  for (long long i = 1; i <= n; ++i) cin >> a[i];
  dp[0][0] = 1;
  for (long long j = 0; j <= K; ++j) {
    pre[j] = dp[0][j] + ((j) ? pre[j - 1] : 0);
    pre[j] %= MOD;
  }
  for (long long i = 1; i <= n; ++i) {
    for (long long j = 0; j <= K; ++j) {
      long long L = max(j - a[i], 0LL);
      long long R = j;
      long long ways = pre[R] - ((L) ? pre[L - 1] : 0);
      dp[i][j] += ways;
      dp[i][j] %= MOD;
    }
    for (long long j = 0; j <= K; ++j) {
      pre[j] = dp[i][j] + ((j) ? pre[j - 1] : 0);
      pre[j] %= MOD;
    }
  }
  cout << dp[n][K];
  return 0;
}
