using System;
using System.Collections.Generic;
using System.Linq;
using System.IO;
//using System.Text;
//using System.Text.RegularExpressions;
//using System.Globalization;
//using System.Diagnostics;
using static System.Console;
//using System.Numerics;
//using static System.Math;
//using pair = Pair<int, int>;

class Program
{
    static void Main()
    {
        //SetOut(new StreamWriter(OpenStandardOutput()) { AutoFlush = false });
        new Program().solve();
        Out.Flush();
    }
    readonly Scanner cin = new Scanner();
    readonly int[] dd = { 0, 1, 0, -1, 0 }; //→↓←↑
    readonly int mod = 1000000007;
    void chmax<T>(ref T a, T b) where T : IComparable<T> { a = a.CompareTo(b) < 0 ? b : a; }
    void chmin<T>(ref T a, T b) where T : IComparable<T> { a = a.CompareTo(b) < 0 ? a : b; }

    void solve()
    {
        int N = cin.nextint;
        int K = cin.nextint;
        var A = cin.scanint;

        //残っている飴がi個のときの組み合わせの数
        var dp = new FenwickTree(K + 2);
        dp.Add(K, 1);
        for (int i = 0; i < N; i++)
        {
            for (int j = 0; j <= K; j++)
            {
                dp.Add(j, dp[j + 1, Math.Min(K + 1, j + A[i])]);
            }
        }
        WriteLine(dp[0, 0]);


    }

}

#region Fenwick
public class FenwickTree
{
    readonly int n;
    readonly ModInt[] bit;
    readonly int max = 1;
    public FenwickTree(int size)
    {
        n = size; bit = new ModInt[n + 1];
        while ((max << 1) <= n) max <<= 1;
    }
    /// <summary>sum[a,b] 0-indexed</summary>
    public ModInt this[int i, int j] { get { i++; j++; return i <= j ? this[j] - this[i - 1] : 0; } }
    /// <summary>sum[0,i] 1-indexed</summary>
    public ModInt this[int i] { get { ModInt s = 0; for (; i > 0; i -= i & -i) s += bit[i]; return s; } }
    //public int LowerBound(int w)
    //{
    //    if (w <= 0) return 0;
    //    int x = 0;
    //    for (int k = max; k > 0; k >>= 1)
    //        if (x + k <= n && bit[x + k] < w)
    //        {
    //            w -= bit[x + k];
    //            x += k;
    //        }
    //    return x + 1;
    //}
    /// <summary>add v to bit[i] 0-indexed</summary>
    public void Add(int i, ModInt v)
    {
        i++;
        if (i == 0) System.Diagnostics.Debug.Fail("BIT is 1 indexed");
        for (; i <= n; i += i & -i) bit[i] += v;
    }
    public ModInt[] Items
    {
        get
        {
            var ret = new ModInt[n + 1];
            for (int i = 0; i < ret.Length; i++)
                ret[i] = this[i, i];
            return ret;
        }
    }
}
#endregion
#region RangeAddFenwick
public class RangeAddFenwickTree
{
    readonly int n;
    FenwickTree a, b;
    public RangeAddFenwickTree(int n)
    {
        this.n = n;
        a = new FenwickTree(n);
        b = new FenwickTree(n);
    }
    /// <summary>Add V to[i,j]</summary>
    public void Add(int i, int j, ModInt v)
    {
        a.Add(i, -(i - 1) * v); a.Add(j + 1, j * v);
        b.Add(i, v); b.Add(j + 1, -1 * v);
    }
    /// <summary>Sum [0,i]</summary>
    public ModInt this[int i] { get { return a[i] + b[i] * i; } }
    /// <summary>Sum [i,j]</summary>
    public ModInt this[int i, int j] { get { return i <= j ? this[j] - this[i - 1] : 0; } }
    public ModInt[] Items
    {
        get
        {
            var ret = new ModInt[n + 1];
            for (int i = 0; i < ret.Length; i++)
                ret[i] = this[i, i];
            return ret;
        }
    }
}
#endregion

#region ModInt
/// <summary>
/// [0,<see cref="Mod"/>) までの値を取るような数
/// </summary>
public struct ModInt
{
    /// <summary>
    /// 剰余を取る値．
    /// </summary>
    public const long Mod = (int)1e9 + 7;

    /// <summary>
    /// 実際の数値．
    /// </summary>
    public long num;
    /// <summary>
    /// 値が <paramref name="n"/> であるようなインスタンスを構築します．
    /// </summary>
    /// <param name="n">インスタンスが持つ値</param>
    /// <remarks>パフォーマンスの問題上，コンストラクタ内では剰余を取りません．そのため，<paramref name="n"/> ∈ [0,<see cref="Mod"/>) を満たすような <paramref name="n"/> を渡してください．このコンストラクタは O(1) で実行されます．</remarks>
    public ModInt(long n) { num = n; }
    /// <summary>
    /// このインスタンスの数値を文字列に変換します．
    /// </summary>
    /// <returns>[0,<see cref="Mod"/>) の範囲内の整数を 10 進表記したもの．</returns>
    public override string ToString() { return num.ToString(); }
    public static ModInt operator +(ModInt l, ModInt r) { l.num += r.num; if (l.num >= Mod) l.num -= Mod; return l; }
    public static ModInt operator -(ModInt l, ModInt r) { l.num -= r.num; if (l.num < 0) l.num += Mod; return l; }
    public static ModInt operator *(ModInt l, ModInt r) { return new ModInt(l.num * r.num % Mod); }
    public static implicit operator ModInt(long n) { n %= Mod; if (n < 0) n += Mod; return new ModInt(n); }

    /// <summary>
    /// 与えられた 2 つの数値からべき剰余を計算します．
    /// </summary>
    /// <param name="v">べき乗の底</param>
    /// <param name="k">べき指数</param>
    /// <returns>繰り返し二乗法により O(N log N) で実行されます．</returns>
    public static ModInt Pow(ModInt v, long k) { return Pow(v.num, k); }

    /// <summary>
    /// 与えられた 2 つの数値からべき剰余を計算します．
    /// </summary>
    /// <param name="v">べき乗の底</param>
    /// <param name="k">べき指数</param>
    /// <returns>繰り返し二乗法により O(N log N) で実行されます．</returns>
    public static ModInt Pow(long v, long k)
    {
        long ret = 1;
        for (k %= Mod - 1; k > 0; k >>= 1, v = v * v % Mod)
            if ((k & 1) == 1) ret = ret * v % Mod;
        return new ModInt(ret);
    }
    /// <summary>
    /// 与えられた数の逆元を計算します．
    /// </summary>
    /// <param name="v">逆元を取る対象となる数</param>
    /// <returns>逆元となるような値</returns>
    /// <remarks>法が素数であることを仮定して，フェルマーの小定理に従って逆元を O(log N) で計算します．</remarks>
    public static ModInt Inverse(ModInt v) { return Pow(v, Mod - 2); }
}
#endregion

#region Binomial Coefficient
public class BinomialCoefficient
{
    public ModInt[] fact, ifact;
    public BinomialCoefficient(int n)
    {
        fact = new ModInt[n + 1];
        ifact = new ModInt[n + 1];
        fact[0] = 1;
        for (int i = 1; i <= n; i++)
            fact[i] = fact[i - 1] * i;
        ifact[n] = ModInt.Inverse(fact[n]);
        for (int i = n - 1; i >= 0; i--)
            ifact[i] = ifact[i + 1] * (i + 1);
        ifact[0] = ifact[1];
    }
    public ModInt this[int n, int r]
    {
        get
        {
            if (n < 0 || n >= fact.Length || r < 0 || r > n) return 0;
            return fact[n] * ifact[n - r] * ifact[r];
        }
    }
    public ModInt RepeatedCombination(int n, int k)
    {
        if (k == 0) return 1;
        return this[n + k - 1, k];
    }
}
#endregion
class Scanner
{
    string[] s; int i;
    readonly char[] cs = new char[] { ' ' };
    public Scanner() { s = new string[0]; i = 0; }
    public string[] scan { get { return ReadLine().Split(); } }
    public int[] scanint { get { return Array.ConvertAll(scan, int.Parse); } }
    public long[] scanlong { get { return Array.ConvertAll(scan, long.Parse); } }
    public double[] scandouble { get { return Array.ConvertAll(scan, double.Parse); } }
    public string next
    {
        get
        {
            if (i < s.Length) return s[i++];
            string st = ReadLine();
            while (st == "") st = ReadLine();
            s = st.Split(cs, StringSplitOptions.RemoveEmptyEntries);
            i = 0;
            return next;
        }
    }
    public int nextint { get { return int.Parse(next); } }
    public long nextlong { get { return long.Parse(next); } }
    public double nextdouble { get { return double.Parse(next); } }
    public void join<T>(IEnumerable<T> values) { WriteLine(string.Join(" ", values)); }
}