#include <bits/stdc++.h>

using namespace std;

#define int long long
// #define double long double
#define FOR(i, a, b) for(ll i = (a); i < (b); ++i)
#define FORR(i, a, b) for(ll i = (a); i > (b); --i)
#define REP(i, n) for(ll i = 0; i < (n); ++i)
#define REPR(i, n) for(ll i = n; i >= 0; i--)
#define FOREACH(x, a) for(auto &(x) : (a))
#define VECCIN(x)                                                              \
    for(auto &youso_ : (x)) cin >> youso_
#define bitcnt __builtin_popcount
#define SZ(x) ((ll)(x).size())
#define fi first
#define se second
#define All(a) (a).begin(), (a).end()
template <typename T = long long> inline T IN() {
    T x;
    cin >> x;
    return (x);
}
inline void CIN() {}
template <class Head, class... Tail>
inline void CIN(Head &&head, Tail &&... tail) {
    cin >> head;
    CIN(move(tail)...);
}
#define CCIN(...)                                                              \
    char __VA_ARGS__;                                                          \
    CIN(__VA_ARGS__)
#define DCIN(...)                                                              \
    double __VA_ARGS__;                                                        \
    CIN(__VA_ARGS__)
#define LCIN(...)                                                              \
    ll __VA_ARGS__;                                                            \
    CIN(__VA_ARGS__)
#define SCIN(...)                                                              \
    string __VA_ARGS__;                                                        \
    CIN(__VA_ARGS__)
#define Printv(v)                                                              \
    {                                                                          \
        REP(x, v.size()) { cout << v[x] << (x == v.size() - 1 ? "\n" : " "); } \
    }
template <typename T = string> inline void eputs(T s) {
    cout << s << "\n";
    exit(0);
}
template <typename A, size_t N, typename T>
void Fill(A (&array)[N], const T &val) {
    std::fill((T *)array, (T *)(array + N), val);
}
template <typename T> using PQG = priority_queue<T, vector<T>, greater<T>>;
template <typename T> using PQ = priority_queue<T>;

typedef long long ll;
typedef vector<ll> VL;
typedef vector<VL> VVL;
typedef pair<ll, ll> PL;

const int INF = 1e9;
const int MOD = 1e9 + 7;
const double PI = atan(1.0) * 4.0;
const ll LINF = 1e18;
const ll dx[] = {1, 0, -1, 0};
const ll dy[] = {0, 1, 0, -1};

template <int MOD> struct Fp {
    long long val;
    constexpr Fp(long long v = 0) noexcept : val(v % MOD) {
        if(val < 0) v += MOD;
    }
    constexpr int getmod() { return MOD; }
    constexpr Fp operator-() const noexcept { return val ? MOD - val : 0; }
    constexpr Fp operator+(const Fp &r) const noexcept {
        return Fp(*this) += r;
    }
    constexpr Fp operator-(const Fp &r) const noexcept {
        return Fp(*this) -= r;
    }
    constexpr Fp operator*(const Fp &r) const noexcept {
        return Fp(*this) *= r;
    }
    constexpr Fp operator/(const Fp &r) const noexcept {
        return Fp(*this) /= r;
    }
    constexpr Fp &operator+=(const Fp &r) noexcept {
        val += r.val;
        if(val >= MOD) val -= MOD;
        return *this;
    }
    constexpr Fp &operator-=(const Fp &r) noexcept {
        val -= r.val;
        if(val < 0) val += MOD;
        return *this;
    }
    constexpr Fp &operator*=(const Fp &r) noexcept {
        val = val * r.val % MOD;
        return *this;
    }
    constexpr Fp &operator/=(const Fp &r) noexcept {
        long long a = r.val, b = MOD, u = 1, v = 0;
        while(b) {
            long long t = a / b;
            a -= t * b;
            swap(a, b);
            u -= t * v;
            swap(u, v);
        }
        val = val * u % MOD;
        if(val < 0) val += MOD;
        return *this;
    }
    constexpr bool operator==(const Fp &r) const noexcept {
        return this->val == r.val;
    }
    constexpr bool operator!=(const Fp &r) const noexcept {
        return this->val != r.val;
    }
    friend constexpr ostream &operator<<(ostream &os,
                                         const Fp<MOD> &x) noexcept {
        return os << x.val;
    }
    friend constexpr istream &operator>>(istream &is, Fp<MOD> &x) noexcept {
        return is >> x.val;
    }
    friend constexpr Fp<MOD> modpow(const Fp<MOD> &a, long long n) noexcept {
        if(n == 0) return 1;
        auto t = modpow(a, n / 2);
        t = t * t;
        if(n & 1) t = t * a;
        return t;
    }
};

using mint = Fp<MOD>;

template <class Monoid> struct SegTree {
    using Func = function<Monoid(Monoid, Monoid)>;
    const Func F;
    const Monoid UNITY;
    int SIZE_R;
    vector<Monoid> dat;

    SegTree(int n, const Func f, const Monoid &unity) : F(f), UNITY(unity) {
        init(n);
    }
    void init(int n) {
        SIZE_R = 1;
        while(SIZE_R < n) SIZE_R *= 2;
        dat.assign(SIZE_R * 2, UNITY);
    }

    /* set, a is 0-indexed */
    void set(int a, const Monoid &v) { dat[a + SIZE_R] = v; }
    void build() {
        for(int k = SIZE_R - 1; k > 0; --k)
            dat[k] += F(dat[k * 2], dat[k * 2 + 1]);
    }

    /* update, a is 0-indexed */
    void update(int a, const Monoid &v) {
        int k = a + SIZE_R;
        dat[k] += v;
        while(k >>= 1) dat[k] = F(dat[k * 2], dat[k * 2 + 1]);
    }

    /* get {min-value, min-index}, a and b are 0-indexed */
    Monoid get(int a, int b) {
        Monoid vleft = UNITY, vright = UNITY;
        for(int left = a + SIZE_R, right = b + SIZE_R; left < right;
            left >>= 1, right >>= 1) {
            if(left & 1) vleft = F(vleft, dat[left++]);
            if(right & 1) vright = F(dat[--right], vright);
        }
        return F(vleft, vright);
    }
    inline Monoid operator[](int a) { return dat[a + SIZE_R]; }

    /* debug */
    void print() {
        for(int i = 0; i < SIZE_R; ++i) {
            cout << (*this)[i];
            if(i != SIZE_R - 1) cout << ",";
        }
        cout << endl;
    }
};

ll N, a[100];
mint dp[101][100001];

signed main() {
    LCIN(N, K);
    REP(i, N) cin >> a[i];
    REP(i, N + 1) dp[i][0] = 1;
    REP(i, N) REP(j, K + 1) {
        if(j - 1 - a[i] >= 0)
            dp[i + 1][j] = dp[i + 1][j - 1] + dp[i][j] - dp[i][j - 1 - a[i]];
        else if(j)
            dp[i + 1][j] = dp[i + 1][j - 1] + dp[i][j];
    }
    cout << dp[N][K] << "\n";
}


Measured memory_bytes: 78336