#include <bits/stdc++.h>
using namespace std;
const int block_size = 320;
const long long mod = 1e9 + 7;
const long long inf = 1e9 + 7;
const long long INF = 1e18 + 5;
const long double eps = 1e-9;
const double PI = atan(1) * 4;
template <typename T>
inline int sign(const T &a) {
  if (a < 0) return -1;
  if (a > 0) return 1;
  return 0;
}
string to_string(string s) { return '"' + s + '"'; }
string to_string(const char *s) { return to_string((string)s); }
string to_string(bool b) { return (b ? "true" : "false"); }
template <typename A, typename B>
string to_string(pair<A, B> p) {
  return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}
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;
}
void debug_out() { cerr << endl; }
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
  cerr << " " << to_string(H);
  debug_out(T...);
}
template <typename T, typename S>
inline bool upmin(T &a, const S &b) {
  return a > b ? a = b, 1 : 0;
}
template <typename T, typename S>
inline bool upmax(T &a, const S &b) {
  return a < b ? a = b, 1 : 0;
}
template <typename T>
inline void in(T &x) {
  x = 0;
  T f = 1;
  char ch = getchar();
  while (!isdigit(ch)) {
    if (ch == '-') f = -1;
    ch = getchar();
  }
  while (isdigit(ch)) {
    x = x * 10 + ch - '0';
    ch = getchar();
  }
  x *= f;
}
long long twop(int x) { return 1LL << x; }
template <typename A, typename B>
inline void in(A &x, B &y) {
  in(x);
  in(y);
}
template <typename A, typename B, typename C>
inline void in(A &x, B &y, C &z) {
  in(x);
  in(y);
  in(z);
}
template <typename A, typename B, typename C, typename D>
inline void in(A &x, B &y, C &z, D &d) {
  in(x);
  in(y);
  in(z);
  in(d);
}
long long gcd(long long a, long long b) { return b == 0 ? a : gcd(b, a % b); }
namespace SOLVE {
void main() {
  int n, k;
  in(n, k);
  vector<long long> mosts(n);
  for (long long i = 0; i < n; i++) {
    in(mosts[i]);
  }
  vector<vector<long long> > memo(n + 5, vector<long long>(k + 5));
  memo[0][k] = 1;
  for (long long child = 1; child <= n; child++) {
    for (long long candies = 0; candies <= k; candies++) {
      memo[child][candies] = 0;
      for (long long lastcandy = 0; lastcandy <= mosts[child - 1];
           lastcandy++) {
        if (candies + lastcandy > k) {
          continue;
        }
        memo[child][candies] += memo[child - 1][candies + lastcandy];
        memo[child][candies] %= mod;
      }
    }
  }
  cout << memo[n][0] << endl;
}
}  // namespace SOLVE
signed main() {
  int t;
  t = 1;
  while (t--) {
    SOLVE::main();
  }
  return 0;
}
