#include<fstream>
using namespace std;
ifstream in("divk.in");
ofstream out("divk.out");
long long k,a,b,n,sum[500001],aparitii[500001],i,apar;
int main()
{
    in>>n>>k>>a>>b;
    for(i=1;i<=n;i++) { in>>sum[i]; sum[i]=(sum[i-1]+sum[i]); sum[i]%=k;}
    for(i=a;i<=n;i++)
    {
        aparitii[sum[i-a]]++;
        if(i>b) aparitii[sum[i-b-1]]--;
        apar+=aparitii[sum[i]];
    }
    out << apar << "\n";
    return 0;
}