#include <bits/stdc++.h>
//qwerty47924692
using namespace std;
using ll = int;
const ll N=1e4+29;
const ll mod=1e9+7;
const string br="617283";
#define sz(a)(ll)a.size()
#define f first
#define s second
ll n,l,r[N],dp[2][N][55],c[N+100][N+100];
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cin>>n>>l;
for(ll i=1;i<=n;i++){
cin>>r[i];
}
c[0][0]=1;
for(ll i=1;i<=n+l;i++){
c[i][0]=1;
for(ll j=1;j<=i;j++){
c[i][j]=c[i-1][j]+c[i-1][j-1];
c[i][j]%=mod;
}
}
dp[0][0][0]=1;
ll x=0;
for(ll i=1;i<=n;i++){
x^=1;
dp[x][0][0]=0;
ll R=r[i];
for(ll j=1;j<=i;j++){
for(ll k=1;k<=l;k++){
dp[x][j][k]=dp[!x][j-1][k-1];
if(k>=R)dp[x][j][k]+=(dp[!x][j][k-R]*1ll*2*j)%mod;
dp[x][j][k]%=mod;
if(k>=2*R-1)dp[x][j][k]+=(dp[!x][j+1][k-2*R+1]*1ll*j*(j+1))%mod;
dp[x][j][k]%=mod;
}
}
}
ll ans=0;
for(ll d=1;d<=l;d++){
ans+=(dp[x][1][d]*1ll*c[l-d+n][n])%mod;
ans%=mod;
}cout<<ans;
}
