#include <fstream>
using namespace std;
ifstream fi("divk.in");
ofstream fo("divk.out");
int a,b,n,k,v[500001],s[100001];
long long sol;

int main()
{
   fi>>n>>k>>a>>b;
   for(int i=1;i<=n;i++)
    {
        fi>>v[i];
        v[i]+=v[i-1];
        v[i]%=k;

        if(i-b-1 >=0) s[v[i-b-1]]--;
        if(i-a   >=0) s[v[i-a  ]]++;
       // for(int j=0;j<=n;j++) fo<<s[j]<<" ";fo<<endl;

        sol+=s[v[i]];
    }


    fo<<sol;
    return 0;
}