#include <iostream>
#include <fstream>

using namespace std;

long long r[500073];
long long numar[100073];
long long solutii;

int main()
{
    int x,n,k,a,b;

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

    in>>n>>k>>a>>b;

    for (int i=1;i<=n;i++)
    {
        in>>x;
        r[i]=(r[i-1]+x)%k;

        if (i>b)
            numar[r[i-b-1]]--;
        if(i>=a)
            numar[r[i-a]]++;
        solutii+=numar[r[i]];
    }
    out<<solutii;
    return 0;
}