#include <iostream>
#include <fstream>
using namespace std;
ifstream f("divk.in");
ofstream g("divk.out");

int n,a,b,k,ap[100001],s[500001],x,sum;

int main()
{f>>n>>k>>a>>b;
 for(int i=1;i<=n;i++)
 {f>>x;
  s[i]=(s[i-1]+x)%k;
  if(i>=a)ap[s[i-a]]++;
  if(i>b) ap[s[i-b-1]]--;
  sum+=ap[s[i]];
 }
 g<<sum<<'\n';

    return 0;
}