#include<bits/stdc++.h>
using namespace std;
using Int = long long;
template<typename T1,typename T2> inline void chmin(T1 &a,T2 b){if(a>b) a=b;}
template<typename T1,typename T2> inline void chmax(T1 &a,T2 b){if(a<b) a=b;}


template<typename T,T MOD = 1000000007>
struct Mint{
  T v;
  Mint():v(0){}
  Mint(signed v):v(v){}
  Mint(long long t){v=t%MOD;if(v<0) v+=MOD;}

  Mint pow(long long k){
    Mint res(1),tmp(v);
    while(k){
      if(k&1) res*=tmp;
      tmp*=tmp;
      k>>=1;
    }
    return res;
  }
  
  Mint inv(){return pow(MOD-2);}
  
  Mint& operator+=(Mint a){v+=a.v;if(v>=MOD)v-=MOD;return *this;}
  Mint& operator-=(Mint a){v+=MOD-a.v;if(v>=MOD)v-=MOD;return *this;}
  Mint& operator*=(Mint a){v=1LL*v*a.v%MOD;return *this;}
  Mint& operator/=(Mint a){return (*this)*=a.inv();}
  
  Mint operator+(Mint a) const{return Mint(v)+=a;};
  Mint operator-(Mint a) const{return Mint(v)-=a;};
  Mint operator*(Mint a) const{return Mint(v)*=a;};
  Mint operator/(Mint a) const{return Mint(v)/=a;};

  Mint operator-(){return v?MOD-v:v;}

  bool operator==(const Mint a)const{return v==a.v;}
  bool operator!=(const Mint a)const{return v!=a.v;}
  bool operator <(const Mint a)const{return v <a.v;}

};
//INSERT ABOVE HERE
using M = Mint<int>;
signed main(){
  int n,k;
  cin>>n>>k;
  vector<int> a(n);
  for(int i=0;i<n;i++) cin>>a[i];
  
  const int MAX = 1e5;
  vector<M> dp(MAX,0);
  dp[0]=M(1);
  for(int i=0;i<n;i++){    
    vector<M> sm(MAX,0);
    for(int j=0;j+1<MAX;j++) sm[j+1]=sm[j]+dp[j];
    vector<M> nx(MAX,0);
    for(int j=0;j+1<MAX;j++) nx[j]=sm[j+1]-sm[max(0,j-i)];
    swap(dp,nx);
  }
  
  M ans;
  for(int i=0;i<=k;i++) ans+=dp[i];  
  cout<<ans.v<<endl;
  return 0;
}