#include <bits/stdc++.h>
template <typename T>
void MACRO_VAR_Scan(T& t) {
  std::cin >> t;
}
template <typename First, typename... Rest>
void MACRO_VAR_Scan(First& first, Rest&... rest) {
  std::cin >> first;
  MACRO_VAR_Scan(rest...);
}
template <typename T>
void MACRO_VEC_ROW_Init(int n, T& t) {
  t.resize(n);
}
template <typename First, typename... Rest>
void MACRO_VEC_ROW_Init(int n, First& first, Rest&... rest) {
  first.resize(n);
  MACRO_VEC_ROW_Init(n, rest...);
}
template <typename T>
void MACRO_VEC_ROW_Scan(int p, T& t) {
  std::cin >> t[p];
}
template <typename First, typename... Rest>
void MACRO_VEC_ROW_Scan(int p, First& first, Rest&... rest) {
  std::cin >> first[p];
  MACRO_VEC_ROW_Scan(p, rest...);
}
template <class T>
inline T CHMAX(T& a, const T b) {
  return a = (a < b) ? b : a;
}
template <class T>
inline T CHMIN(T& a, const T b) {
  return a = (a > b) ? b : a;
}
template <class T>
std::vector<std::vector<T>> VV(int n, int m, T init = T()) {
  return std::vector<std::vector<T>>(n, std::vector<T>(m, init));
}
template <typename S, typename T>
std::ostream& operator<<(std::ostream& os, std::pair<S, T> p) {
  os << "(" << p.first << ", " << p.second << ")";
  return os;
}
using ll = long long;
using ull = unsigned long long;
using ld = long double;
using PAIR = std::pair<ll, ll>;
using PAIRLL = std::pair<ll, ll>;
constexpr ll INFINT = 1 << 30;
constexpr ll INFINT_LIM = (1LL << 31) - 1;
constexpr ll INFLL = 1LL << 60;
constexpr ll INFLL_LIM = (1LL << 62) - 1 + (1LL << 62);
constexpr double EPS = 1e-10;
constexpr ll MOD = 1000000007;
constexpr double PI = 3.141592653589793238462643383279;
template <class T, size_t N>
void FILL(T (&a)[N], const T& val) {
  for (auto& x : a) x = val;
}
template <class ARY, size_t N, size_t M, class T>
void FILL(ARY (&a)[N][M], const T& val) {
  for (auto& b : a) FILL(b, val);
}
template <class T>
void FILL(std::vector<T>& a, const T& val) {
  for (auto& x : a) x = val;
}
template <class ARY, class T>
void FILL(std::vector<std::vector<ARY>>& a, const T& val) {
  for (auto& b : a) FILL(b, val);
}
enum QUERY { SUM, MAX, MIN };
template <class T = ll>
class SegmentTree {
 private:
  ll ARY_SIZE;
  T init_val;
  std::vector<T> ary;
  std::function<T(T, T)> func;

 public:
  SegmentTree(ll n, QUERY qtype) : ARY_SIZE(1) { init(n, qtype); }
  SegmentTree(ll n, T init_val, QUERY qtype) : ARY_SIZE(1) {
    init(n, init_val, qtype);
  }
  void init(ll n, QUERY qtype) {
    T init_val;
    switch (qtype) {
      case SUM:
        init_val = 0;
        break;
      case MAX:
        init_val = std::numeric_limits<T>::lowest();
        break;
      case MIN:
        init_val = std::numeric_limits<T>::max();
        break;
      default:
        struct INVALID_QUERY_TYPE_ERROR {};
        throw INVALID_QUERY_TYPE_ERROR();
        break;
    }
    init(n, init_val, qtype);
  }
  void init(ll n, T init_val, QUERY qtype) {
    std::function<T(T, T)> f;
    switch (qtype) {
      case SUM:
        f = [](T l, T r) { return l + r; };
        break;
      case MAX:
        f = [](T l, T r) { return std::max(l, r); };
        break;
      case MIN:
        f = [](T l, T r) { return std::min(l, r); };
        break;
      default:
        struct INVALID_QUERY_TYPE_ERROR {};
        throw INVALID_QUERY_TYPE_ERROR();
        break;
    }
    init(n, init_val, f);
  }
  void init(ll n, T init_val, std::function<T(T, T)> f) {
    while (ARY_SIZE < n) ARY_SIZE <<= 1;
    ARY_SIZE = ARY_SIZE * 2 - 1;
    ary.resize(ARY_SIZE, init_val);
    this->init_val = init_val;
    func = f;
  }
  void update(ll i, T val) {
    i += ARY_SIZE / 2;
    ary[i] = val;
    while (i > 0) {
      i = (i - 1) / 2;
      ary[i] = func(ary[2 * i + 1], ary[2 * i + 2]);
    }
  }
  void add(ll i, T val) {
    i += ARY_SIZE / 2;
    ary[i] += val;
    while (i > 0) {
      i = (i - 1) / 2;
      ary[i] = func(ary[2 * i + 1], ary[2 * i + 2]);
    }
  }
  T query_(ll a, ll b, ll i, ll l, ll r) {
    if (r <= a || b <= l) return init_val;
    if (a <= l && r <= b)
      return ary[i];
    else {
      T vl = query_(a, b, 2 * i + 1, l, (l + r) / 2);
      T vr = query_(a, b, 2 * i + 2, (l + r) / 2, r);
      return func(vl, vr);
    }
  }
  T query(ll a, ll b) { return query_(a, b, 0, 0, ARY_SIZE / 2 + 1); }
  T operator[](ll i) { return ary[i + ARY_SIZE / 2]; }
  void debug_show() {
    for (ll i = ARY_SIZE / 2; i < ARY_SIZE; ++i) std::cerr << ary[i] << " ";
    std::cerr << "\n";
  }
};
using ST = SegmentTree<ll>;
signed main() {
  std::ios::sync_with_stdio(false);
  std::cin.tie(0);
  ;
  ll n, k;
  MACRO_VAR_Scan(n, k);
  ;
  std::vector<ll> a(n);
  for (auto& i : a) std::cin >> i;
  ;
  std::vector<ST> dp(n + 1, ST(k + 1, SUM));
  dp[0].update(0, 1);
  for (ll i = 0; i < ll(n); ++i)
    for (ll j = 0; j < ll(k + 1); ++j) {
      ll l = j - a[i];
      if (l < 0) l = 0;
      dp[i + 1].update(j, dp[i].query(l, j + 1) % MOD);
    }
  std::cout << (dp[n].query(k, k + 1) % MOD);
  std::cout << "\n";
  ;
  return 0;
}
