// Author: Teoman Ata Korkmaz
#pragma GCC optimize("O3,unroll-loops,inline")
#include <bits/stdc++.h>
#pragma GCC target("avx,avx2,bmi,bmi2,popcnt")
#define int int_fast64_t
using namespace std;
constexpr int N=1e4+4;
constexpr int MOD=1e9+7;
///////////////////////////////////////////////////////////
int n,l,fact[N],inv_fact[N];
//int32_t dp[N][N];//partition K (i) into N (j)
vector<int> v;
inline int fp(int b,int p){
int ans=1;
while(p){
if(p&1)ans=(ans*b)%MOD;
p>>=1;
b=(b*b)%MOD;
}
return ans;
}
inline int nCr(int n,int r){
return (((fact[n]*inv_fact[r])%MOD)*inv_fact[n-r])%MOD;
}
signed main(void){
fact[0]=1;for(int i=1;i<N;i++)fact[i]=(fact[i-1]*i)%MOD;
for(int i=0;i<N;i++)inv_fact[i]=fp(fact[i],MOD-2);
//cerr<<"inv_Fact: ";for(int i=0;i<5;i++)cerr<<inv_fact[i]<<" ";cerr<<endl;
/*for(int n=0;n<5;n++){
for(int r=0;r<n;r++){
cerr<<"nCr("<<n<<","<<r<<")="<<nCr(n,r)<<endl;
}
}*/
/*for(size_t k=0;k<5;k++){
cerr<<"dp: ";
for(size_t n=0;n<5;n++){
cerr<<dp[k][n]<<" ";
}
cerr<<endl;
}cerr<<endl;*/
cin>>n>>l;
if(n==1){
cout<<l<<endl;
exit(0);
}
v.resize(n);
for(auto& i:v){cin>>i;i--;}
int range_size=0;
for(int i=0;i<n;i++)range_size+=2*v[i]+1;
/*for(int n=0;n<5;n++){
for(int r=0;r<n;r++){
cerr<<"nCr("<<n<<","<<r<<")="<<nCr(n,r)<<endl;
}
}*/
int ans=0;
for(int start=0;start<n;start++){
for(int stop=0;stop<n;stop++){
if(start==stop)continue;
int step=l-(range_size-v[start]-v[stop]);
if(step<0)continue;
//cerr<<"yippe"<<endl;
//cerr<<"fact: ";for(int i=0;i<5;i++)cerr<<fact[i]<<" ";cerr<<endl;
//cerr<<"nCr("<<n<<","<<step<<")="<<nCr(n,step)<<endl;
ans+=nCr(l,step);
//cerr<<"start stop step: "<<start<<" "<<stop<<" "<<step<<endl;
//cerr<<"ans: "<<ans<<endl;
ans%=MOD;
}
}
ans%=MOD;
ans*=fact[n-2];
ans%=MOD;
cout<<ans<<endl;
}
