#pragma GCC optimize("Ofast","unroll-loops")
#pragma comment(linker, "/stack:200000000")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#include<bits/stdc++.h>
using namespace::std;
//struct __INIT{__INIT(){cin.tie(0);ios::sync_with_stdio(false);cout<<fixed<<setprecision(15);}} __init;
__attribute__((constructor))
void init(){
	cin.tie(0);
	ios::sync_with_stdio(false);
	cout<<fixed<<setprecision(15);
}
// random_device rd;
// mt19937 mt(rd());
// #include <boost/numeric/interval.hpp>
// #include <boost/numeric/interval/io.hpp>
// #include <boost/intrusive/rbtree.hpp>
// #include <boost/dynamic_bitset.hpp>
// #include <boost/geometry.hpp>
// #include <boost/geometry/geometries/linestring.hpp>
// #include <boost/geometry/geometries/polygon.hpp>
// #include <boost/geometry/geometries/point_xy.hpp>
// #include <boost/math/tools/minima.hpp>
// using boost::math::tools::brent_find_minima;
// #include <boost/multiprecision/cpp_dec_float.hpp>
// #include <boost/multiprecision/cpp_int.hpp>
// namespace mp = boost::multiprecision;
// typedef mp::number<mp::cpp_dec_float<256>> cdouble;
// typedef mp::cpp_int cint;
// #include <boost/unordered_map.hpp>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/priority_queue.hpp>
#include<ext/pb_ds/tag_and_trait.hpp>
template<typename T=long long>using pbds=__gnu_pbds::tree<T,__gnu_pbds::null_type,less<T>,__gnu_pbds::rb_tree_tag,__gnu_pbds::tree_order_statistics_node_update>;
template<typename T=long long>using pbds_map=__gnu_pbds::tree<T,T,less<T>,__gnu_pbds::rb_tree_tag,__gnu_pbds::tree_order_statistics_node_update>;
template<typename T=long long>using pqueue =__gnu_pbds::priority_queue<T, less<T>,__gnu_pbds::rc_binomial_heap_tag>;
typedef long long lint;
typedef long long ll;
typedef long double ldouble;
typedef vector<lint> vec;
typedef vector<vector<lint>> mat;
typedef vector<vector<vector<lint>>> mat3;
typedef vector<double> dvec;
typedef vector<vector<double>> dmat;
typedef vector<vector<vector<double>>> dmat3;
typedef vector<string> svec;
typedef vector<vector<string>> smat;
typedef vector<vector<vector<string>>> smat3;
template<typename T>using Vec=vector<T>;
template<typename T>using Mat=vector<vector<T>>;
template<typename T>using Mat3=vector<vector<vector<T>>>;
template<typename T>using Mat4=vector<vector<vector<vector<T>>>>;
template<typename S,typename T>using pvec=vector<pair<S,T>>;
template<typename S,typename T>using pmat=vector<vector<pair<S,T>>>;
template<typename S,typename T>using pmat3=vector<vector<vector<pair<S,T>>>>;
template<typename S,typename T>using pmat4=vector<vector<vector<vector<pair<S,T>>>>>;
template<typename... T>using tvec=vector<tuple<T...>>;
template<typename... T>using tmat=vector<vector<tuple<T...>>>;
template<typename... T>using tmat3=vector<vector<vector<tuple<T...>>>>;
template<typename... T>using tmat4=vector<vector<vector<vector<tuple<T...>>>>>;
#define rep(i, n) for(lint i = 0; i < (lint)(n); i++)
#define irep(i) for(lint i = 0;; i++)
#define irep1(i) for(lint i = 1;; i++)
#define irep2(i) for(lint i = 2;; i++)
#define rrep(i, n) for(lint i = (lint)(n-1); i >-1; i--)
#define rrepi(i,a,b) for(lint i = (lint)(b-1); i >a-1; i--)
#define repi(i,a,b) for(lint i=lint(a);i<lint(b);i++)
#define rep2(i,a,b,c) for(lint i=lint(a);i>lint(b);i+=c)
#define all(x) (x).begin(),(x).end()
#define PI 3.141592653589793
#define dist(x1,y1,x2,y2) (pow(pow(x2-x1,2)+pow(y2-y1,2),0.5))
//#define input(a,n) lint n;cin>>n;vector<lint>a(n);rep(i,n)cin>>a[i];
#define SUM(v) accumulate(all(v),0LL)
#define INF (1LL<<60)
#define IINF (1<<30)
#define EPS (1e-10)
#define LINF 9223372036854775807
//#define MOD 998244353LL
#define MOD 1000000007LL
#define endl "\n"
template<typename T>inline void numout(T t){bool f=0;for(auto i:t){cout<<(f?" ":"")<<i<INF/2?i:"INF";f=1;}cout<<endl;}
template<typename T>inline void numout2(T t){for(auto i:t)numout(i);}
template<typename T>inline void output(T t){bool f=0;for(auto i:t){cout<<(f?" ":"")<<i;f=1;}cout<<endl;}
template<typename T>inline void output2(T t){for(auto i:t)output(i);}
template<typename T>inline void _output(T t){bool f=0;for(int i=0;i<t.size();i++){cout<<f?"":" "<<t[i];f=1;}cout<<endl;}
template<typename T>inline void _output2(T t){for(int i=0;i<t.size();i++)output(t[i]);}
auto Y=[&](auto f){return[&](auto... args){return f(f, args...);};};
template<typename T=lint>T in(){return *istream_iterator<T>(cin);}
template<typename T=lint>inline T gcd(T a,T b){return b?gcd(b,a%b):a;}
template<typename T=lint>inline T lcm(T a,T b){return a/gcd(a,b)*b;}
template<typename T>inline T minq(T a,T b){return min(a,b);}
template<typename T>inline T maxq(T a,T b){return max(a,b);}
inline bool chmin(auto& s,const auto& t){bool res=s>t;s=min(s,t);return res;}
inline bool chmax(auto& s,const auto& t){bool res=s<t;s=max(s,t);return res;}
const vector<lint> dx={-1,1,0,0,1,1,-1,-1};
const vector<lint> dy={0,0,-1,1,1,-1,1,-1};

template<typename T>
class FPS{
    class FFT{
        using u64 = std::uint_fast64_t;
        using C=complex<double>;
        int n=1;
        public:
        vector<T> mul(const vector<T>& a,const vector<T>& b,const int& sz){
            const int size=a.size()+b.size()-1;
            int h=0;
            while(n<size)n<<=1,++h;
            auto c=itoc(b,a,n);
            auto ic=fft(c,h,false);
            vector<C> ires(n);
            for(int i=0;i<n;++i){
                int j=i==0?0:n-i;
                ires[i]=(ic[i]+conj(ic[j]))*(ic[i]-conj(ic[j]))*C(0,-.25);
            }
            auto res=ctoi(fft(ires,h,true),sz);
            return res;
        }
        private:
        vector<C> itoc(const vector<T>& s,const vector<T>& t,const int& n){
            vector<C> res(n);
            for(int i=0;i<n;++i)res[i]=C(i<(int)s.size()?cast(s[i]):0.,i<(int)t.size()?cast(t[i]):0);
            return res;
        }
        vector<T> ctoi(const vector<C>& v,const int& size){
            vector<T> res(size);
            for(int i=0;i<min<int>(size,v.size());i++)res[i]=recast(v[i].real());
            return res;
        }
        vector<C> fft(vector<C> v,const int& h,const bool& inv){
            int n=v.size(),mask=n-1;
            assert((n&(n-1))==0);;
            vector<C> tmp(n);
            C table[n];
            double theta =2*M_PI*(inv?-1:1)/n;
            C zeta(cos(theta),sin(theta));
            table[0]=1;
            for(int i=1;i<n;++i)table[i]=table[i-1]*zeta;
            for(int j=n>>1,t=h-1;j>=1;j>>=1,--t) {
                for(int k=0;k<n;++k){
                    int s=k&(j-1); // T は 下 t 桁
                    int i=k>>t; // i は 上 h - t 桁
                    tmp[k]=v[((i<<(t+1))|s)&mask]+table[i*j]*v[((i<<(t+1))|j|s)&mask];
                    // ζ_(2^(h - t))^i
                }
                swap(v,tmp);
            }
            if(inv)for(int i=0;i<n;++i)v[i]/=n;
            return v;
        }
        inline double cast(const T& t){
            return t.a;
        }
        inline T recast(const double& t){
            return round(t-floor(t/MOD)*MOD);
        }
    };
    vector<T>v;
    static int sz;
    public:
    FPS(){v.resize(sz);}
    inline constexpr FPS operator+=(const FPS& rhs)noexcept{for(int i=0;i<sz;i++)v[i]+=rhs.v[i];return *this;}
    inline constexpr FPS operator-=(const FPS& rhs)noexcept{for(int i=0;i<sz;i++)v[i]-=rhs.v[i];return *this;}
    inline constexpr FPS operator*=(const FPS& rhs)noexcept{v=FFT().mul(v,rhs.v,sz);return *this;}
    inline constexpr FPS operator+(const FPS& rhs)const noexcept{return FPS(*this)+=rhs;}
    inline constexpr FPS operator-(const FPS& rhs)const noexcept{return FPS(*this)-=rhs;}
    inline constexpr bool operator!=(const FPS& rhs)const noexcept{return v!=rhs.v;}
    inline constexpr bool operator==(const FPS& rhs)const noexcept{return v==rhs.v;}
    inline constexpr T& operator[](const int& i)noexcept{return v[i];}
    static void set_size(const int& size){
        sz=size;
    }
};
template<typename T>int FPS<T>::sz;
class mint {
  using u64 = std::uint_fast64_t;
    public:
    u64 a;
    constexpr mint(const u64 x = 0) noexcept : a(x % MOD) {}
    constexpr u64 &value() noexcept { return a; }
    constexpr const u64 &value() const noexcept { return a; }
    constexpr mint operator+(const mint rhs) const noexcept {
        return mint(*this) += rhs;
    }
    constexpr mint operator-(const mint rhs) const noexcept {
        return mint(*this) -= rhs;
    }
    constexpr mint operator*(const mint rhs) const noexcept {
        return mint(*this) *= rhs;
    }
    constexpr mint operator/(const mint rhs) const noexcept {
        return mint(*this) /= rhs;
    }
    constexpr mint &operator+=(const mint rhs) noexcept {
        a += rhs.a;
        if (a >= MOD) {
            a -= MOD;
        }
        return *this;
    }
    constexpr mint &operator-=(const mint rhs) noexcept {
        if (a < rhs.a) {
            a += MOD;
        }
        a -= rhs.a;
        return *this;
    }
    constexpr mint &operator*=(const mint rhs) noexcept {
        a = a * rhs.a % MOD;
        return *this;
    }
    constexpr mint operator++(int n) const noexcept {
        return mint(*this) +=1;
    }
    constexpr mint operator--(int n) const noexcept {
        return mint(*this) -=1;
    }
    constexpr mint &operator/=(mint rhs) noexcept {
        u64 exp = MOD - 2;
        while (exp) {
            if (exp % 2) {
                *this *= rhs;
            }
            rhs *= rhs;
            exp /= 2;
        }
        return *this;
    }
};
ostream& operator<<(ostream& lhs, const mint& rhs) noexcept {
    lhs << rhs.a;
    return lhs;
}
istream& operator>>(istream& lhs,mint& rhs) noexcept {
    lhs >> rhs.a;
    return lhs;
}
inline mint pow(mint m,lint n){
    if(n==0)return 1;
    else if(n%2==0){
        mint x=pow(m,n/2);
        return x*x;
    }else{
        return m*pow(m,n-1);
    }
}
inline mint fact(lint a){
    return a?fact(a-1)*a:1;
}
 
int main(){
    lint n,k;
    cin>>n>>k;
    vec a(n);
    rep(i,n)cin>>a[i];
    FPS<mint>::set_size(k+1);
    FPS<mint> dp;
    dp[0]=1;
    rep(i,n){
        FPS<mint>tmp;
        rep(j,a[i]+1){
            tmp[j]=1;
        }
        dp*=tmp;
    }
    cout<<dp[k]<<endl;
}