#include <fstream>

using namespace std;

ifstream fin("divk.in");
ofstream fout("divk.out");

int n,k,a,b,i,nra[100001],h,v[500001],s,nrb[100001],sa,sb;
long long rez;

int main()
{
    fin>>n>>k>>a>>b;
    for(i=1;i<=n;i++)
    {
        fin>>v[i];
        s=(s+v[i])%k;
        if(i>=a)
        {
            sa=(sa+v[i-a])%k;
            nra[sa]++;
            rez+=nra[s];
        }
        if(i>b)
        {
            sb=(sb+v[i-b-1])%k;
            nrb[sb]++;
            rez-=nrb[s];
        }

    }
    fout<<rez;
    return 0;
}