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