#include <bits/stdc++.h>
using namespace std;

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

#define NMAX 500005

int n,k,a,b;
int v[NMAX];
int sum[NMAX];
int ap[100005];



int main()
{
    fin>>n>>k>>a>>b;
    for(int i=1;i<=n;i++)
    {
        fin>>v[i];
        v[i] = v[i] % k;
    }

    for(int i=1;i<=n;i++)
    {
        sum[i] = (sum[i-1] % k + v[i] % k) % k;
    }

    int sol = 0;
    for(int i=1;i<=n;i++)
    {
        if(i >= a)
        {
            ap[v[i-a]]++;
        }
        if(i > b)
        {
            ap[v[i-b-1]]--;
        }
        sol += ap[v[i]];
    }
    fout<<sol;

    return 0;
}