#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;
using ld = long double;
using vll = vector<ll>;
using vvll = vector<vll>;
using pll = pair<ll, ll>;
using tll = tuple<ll, ll, ll>;
template <typename Head>
void dump_1(const char* str, Head&& h) {
  cerr << str << ": " << h << '\n';
}
template <typename Head, typename... Tail>
void dump_1(const char* str, Head&& h, Tail&&... t) {
  while (*str != ',') {
    cerr << *str++;
  }
  cerr << ": " << h << ' ';
  dump_1(str + 1, t...);
}
template <typename T1, typename T2>
ostream& operator<<(ostream& os, const pair<T1, T2>& v) {
  os << '(' << v.first << ", " << v.second << ')';
  return os;
}
template <typename T1, typename T2, typename T3>
ostream& operator<<(ostream& os, const tuple<T1, T2, T3>& v) {
  os << '(' << get<0>(v) << ", " << get<1>(v) << ", " << get<2>(v) << ')';
  return os;
}
template <typename T>
ostream& operator<<(ostream& os, const vector<T>& v) {
  for (auto it = v.begin(); it != v.end(); it++) {
    if (it != v.begin()) {
      os << ' ';
    }
    os << *it;
  }
  return os;
}
template <typename T>
ostream& operator<<(ostream& os, const set<T>& v) {
  for (auto it = v.begin(); it != v.end(); it++) {
    if (it != v.begin()) {
      os << ' ';
    }
    os << *it;
  }
  return os;
}
template <typename T>
ostream& operator<<(ostream& os, const multiset<T>& v) {
  for (auto it = v.begin(); it != v.end(); it++) {
    if (it != v.begin()) {
      os << ' ';
    }
    os << *it;
  }
  return os;
}
template <typename T1, typename T2>
ostream& operator<<(ostream& os, const map<T1, T2>& v) {
  os << '{';
  for (auto it = v.begin(); it != v.end(); it++) {
    if (it != v.begin()) {
      os << ", ";
    }
    os << it->first << ':' << it->second;
  }
  os << '}';
  return os;
}
void Yes(void) { cout << "Yes\n"; }
void No(void) { cout << "No\n"; }
void YES(void) { cout << "YES\n"; }
void NO(void) { cout << "NO\n"; }
template <typename T>
bool chmax(T& a, const T& b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <typename T>
bool chmin(T& a, const T& b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <typename T>
void vin(vector<T>& v, ll len) {
  for (ll i = 0; i < (len); i++) {
    cin >> v[i];
  }
}
template <typename Head>
void in_1(Head& h) {
  cin >> h;
}
template <typename Head, typename... Tail>
void in_1(Head& h, Tail&... t) {
  cin >> h;
  in_1(t...);
}
template <typename Head>
void print_1(Head&& h) {
  cout << h << '\n';
}
template <typename Head, typename... Tail>
void print_1(Head&& h, Tail&&... t) {
  cout << h << ' ';
  print_1(t...);
}
const ll mod = 1e9 + 7;
struct mint {
  ll x;
  mint(ll x = 0) : x((x % mod + mod) % mod) {}
  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 {
    mint res(*this);
    return res += a;
  }
  mint operator-(const mint a) const {
    mint res(*this);
    return res -= a;
  }
  mint operator*(const mint a) const {
    mint res(*this);
    return res *= a;
  }
  mint pow(ll 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 {
    mint res(*this);
    return res /= a;
  }
  friend ostream& operator<<(ostream& os, const mint& v) {
    os << v.x;
    return os;
  }
};
mint dp[2][100005];
void solve() {
  ll N, K;
  in_1(N, K);
  vll A(N);
  vin(A, N);
  ll i1 = 1;
  ll i2 = 0;
  dp[i2][0] = 1;
  for (ll i = 0; i < (N); i++) {
    i1 ^= 1;
    i2 ^= 1;
    for (ll k = 0; k < (K + 1); k++) {
      dp[i2][k] = dp[i1][k];
    }
    for (ll j = (1); j < (A[i] + 1); j++) {
      for (ll k = 0; k < (K + 1 - j); k++) {
        dp[i2][k + j] += dp[i1][k];
      }
    }
  }
  print_1(dp[i2][K]);
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout << fixed << setprecision(16);
  cerr << fixed << setprecision(16);
  solve();
}
