#include <bits/stdc++.h>
using namespace std;
ifstream in("divk.in");
ofstream out("divk.out");
int v[500008],f[500008];
int main()
{  int a,b,k,n,j,ans=0;
  in>>n>>k>>a>>b;
    for(int i=1;i<=n;i++)
        {in>>v[i]; v[i]=(v[i-1]+v[i]);}
   for(int i=1;i<=n;i++)
   {  f[v[i-a]%k]++;
       if(i>=b)
           f[v[i-b-1]%k]--;
       ans+=f[v[i]%k];
   }out<<ans;

    return 0;
}