#include<bits/stdc++.h>
#define rep(i,a,b) for(int i=a;i<b;i++)
#define rrep(i,a,b) for(int i=a;i>=b;i--)
#define fore(i,a) for(auto &i:a)
#define all(x) (x).begin(),(x).end()
//#pragma GCC optimize ("-O3")
using namespace std;
typedef long long ll; const int inf = INT_MAX / 2; const ll infl = 1LL << 60;
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; }
//---------------------------------------------------------------------------------------------------
template<int MOD> struct ModInt {
    static const int Mod = MOD; unsigned x; ModInt() : x(0) { }
    ModInt(signed sig) { x = sig < 0 ? sig % MOD + MOD : sig % MOD; }
    ModInt(signed long long sig) { x = sig < 0 ? sig % MOD + MOD : sig % MOD; }
    int get() const { return (int)x; }
    ModInt &operator+=(ModInt that) { if ((x += that.x) >= MOD) x -= MOD; return *this; }
    ModInt &operator-=(ModInt that) { if ((x += MOD - that.x) >= MOD) x -= MOD; return *this; }
    ModInt &operator*=(ModInt that) { x = (unsigned long long)x * that.x % MOD; return *this; }
    ModInt &operator/=(ModInt that) { return *this *= that.inverse(); }
    ModInt operator+(ModInt that) const { return ModInt(*this) += that; }
    ModInt operator-(ModInt that) const { return ModInt(*this) -= that; }
    ModInt operator*(ModInt that) const { return ModInt(*this) *= that; }
    ModInt operator/(ModInt that) const { return ModInt(*this) /= that; }
    ModInt inverse() const { long long a = x, b = MOD, u = 1, v = 0;
        while (b) { long long t = a / b; a -= t * b; std::swap(a, b); u -= t * v; std::swap(u, v); }
        return ModInt(u); }
    bool operator==(ModInt that) const { return x == that.x; }
    bool operator!=(ModInt that) const { return x != that.x; }
    ModInt operator-() const { ModInt t; t.x = x == 0 ? 0 : Mod - x; return t; }
};
template<int MOD> ostream& operator<<(ostream& st, const ModInt<MOD> a) { st << a.get(); return st; };
template<int MOD> ModInt<MOD> operator^(ModInt<MOD> a, unsigned long long k) {
    ModInt<MOD> r = 1; while (k) { if (k & 1) r *= a; a *= a; k >>= 1; } return r; }
typedef ModInt<1000000007> mint;
template<class V> struct BIT {
    BIT() {}  // [L, R)
    int NV;vector<V> bit;
    BIT(int n){ init(n); }
    void init(int n) { NV = 1; while (NV < n)NV *= 2; bit.resize(NV); clear(); }
    V operator[](int e) { V s = 0; e++; while (e) s += bit[e - 1], e -= e&-e; return s; }
    void add(int e, V v) { e++; while (e <= NV) bit[e - 1] += v, e += e&-e; }
    int lower_bound(V val) { 
        V tv = 0; int i, ent = 0; for (i = NV - 1; i >= 0; i--)
        if(tv+bit[ent+(1<<i)-1]<=val)tv+=bit[ent+(1<<i)-1],ent += (1 << i);return ent;
    }
    V get(int L, int R) {
        assert(0 <= L); assert(R <= NV); assert(L <= R);
        V res = 0; if(R) res += operator[](R - 1); if (L) res -= operator[](L - 1);return res;
    }
    void clear() { rep(i, 0, NV) bit[i] = 0; }
};
/*---------------------------------------------------------------------------------------------------
　　　　　　　　　　　 ∧＿∧  
　　　　　 ∧＿∧ 　（´<_｀ ）　 Welcome to My Coding Space!
　　　　 （ ´_ゝ`）　/　 ⌒i     
　　　　／　　　＼　 　  |　|     
　　　 /　　 /￣￣￣￣/　　|  
　 ＿_(__ﾆつ/　    ＿/ .| .|＿＿＿＿  
　 　　　＼/＿＿＿＿/　（u　⊃  
---------------------------------------------------------------------------------------------------*/

int N, K, A[101];
BIT<mint> dp[101];
//---------------------------------------------------------------------------------------------------
int main() {
    cin >> N >> K;
    rep(i, 0, N) cin >> A[i];

    rep(i, 0, N+1) dp[i].init(K+2);
    dp[0].add(1,1);

    rep(i, 1, N+1){
        rep(j, 1, K+2){
            int l = max(1, j - A[i-1]);
            int r = j + 1;
            dp[i].add(j, dp[i-1].get(l, r));
        }
    }


    cout << dp[N].get(K+1, K+2) << endl;
}


Measured memory_bytes: 52352