#include <fstream>
#include <iostream>
#define NMAX 500000

using namespace std;

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

int n, k, a, b;
long long sp[NMAX+10], nr[NMAX+10], sol;

int main()
{
    f >> n >> k >> a >> b;
    for(int i=1; i<=n; i++)
        {   long long x;
            f >> x;
            sp[i] = (sp[i] + x) % k;
            if(i >= a)
                {   nr[sp[i-a]]++;
                    if(i > b) nr[sp[i-b-1]]++;
                    sol += nr[sp[i]];
                }
        }
    g << sol << '\n';
    return 0;
}