#include <fstream>
using namespace std;

const int N=500001,M=100001;
int v[N],nr[M],n,k;

ifstream in("dik.in");
ofstream out("divk.out");

int main()
{
    int i,a,b;
    in>>n>>k>>a>>b;
    for (i=1;i<=n;i++)
    {
        in>>v[i];
        v[i]=(v[i-1+v[i])%k;
    }
    for (i=a;i<=n;i++)
    {
        if (b<i)
            nr[v[i-b-1]]--;
        nr[v[i-a]]++;
        R+=nr[v[i]];
    }
    out<<R<<"\n";
    return 0;
}