#include<fstream>
using namespace std;
ifstream in("divk.in");
ofstream o("divk.out");
long long a1,b,k,n,s,i,v[500201],a[500201];
int main(){
 in>>n>>k>>a1>>b;
 for(i=1;i<=n;++i){in>>v[i];v[i]=(v[i-1]+v[i])%k;}
 for(i=a1;i<=n;++i){
  a[v[i-a1]]++;
  if(i>b){a[v[i-b-1]]--;}
  s+=a[v[i]];
 }
 o<<s<<'\n';
 return 0;
}