#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using VI = vector<ll>;
using VV = vector<VI>;
using VS = vector<string>;
using PII = pair<ll, ll>;
template <typename A, typename B>
string to_string(pair<A, B> p);
template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p);
template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p);
string to_string(const string &s) { return '"' + s + '"'; }
string to_string(const char *s) { return to_string((string)s); }
string to_string(bool b) { return (b ? "true" : "false"); }
string to_string(vector<bool> v) {
  bool first = true;
  string res = "{";
  for (int i = 0; i < static_cast<int>(v.size()); i++) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(v[i]);
  }
  res += "}";
  return res;
}
template <size_t N>
string to_string(bitset<N> v) {
  string res = "";
  for (size_t i = 0; i < N; i++) {
    res += static_cast<char>('0' + v[i]);
  }
  return res;
}
template <typename A>
string to_string(A v) {
  bool first = true;
  string res = "{";
  for (const auto &x : v) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(x);
  }
  res += "}";
  return res;
}
template <typename A, typename B>
string to_string(pair<A, B> p) {
  return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}
template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " +
         to_string(get<2>(p)) + ")";
}
template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " +
         to_string(get<2>(p)) + ", " + to_string(get<3>(p)) + ")";
}
void debug_out() { cerr << '\n'; }
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
  cerr << " " << to_string(H);
  debug_out(T...);
}
template <class T>
bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T>
bool chmin(T &a, const T &b) {
  if (b < a) {
    a = b;
    return 1;
  }
  return 0;
}
void no() {
  cout << ("NO") << '\n';
  exit(0);
}
void yes() {
  cout << ("YES") << '\n';
  exit(0);
}
const ll mod = 1e9 + 7;
const ll inf = 1e18;
const double PI = acos(-1);
ll dp[110][100010];
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  ll N, K;
  cin >> N >> K;
  if (K > 999) {
    assert(false);
  }
  VI A(N);
  for (ll i = (0); i < (N); ++i) {
    cin >> A[i];
  }
  dp[0][0] = 1;
  ll sum = 0;
  for (ll i = (1); i < (N + 1); ++i) {
    ll a = A[i - 1];
    sum += a;
    for (ll j = (0); j < (sum + 1); ++j) {
      for (ll k = (0); k < (a + 1); ++k) {
        if (j - k < 0) continue;
        dp[i][j] += dp[i - 1][j - k];
        dp[i][j] %= mod;
      }
    }
  }
  ll ans = dp[N][K];
  cout << (ans) << '\n';
  return 0;
}
