#include <iostream>
#include <fstream>
#define MAXN 500001
#define MAXK 100001

using namespace std;

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

int n,k,a,b;
long long r[MAXN],counter[MAXK],sol;

int main()
{
    int i,x;
    f >> n >> k >> a >> b;
    r[0] = 0;
    for(i=1;i<=n;i++){
        f >> x;
        r[i] = (r[i-1] + x) % k;

        if (i > b)
            counter[r[i-b-1]]--;
        if(i >= a)
            counter[r[i-a]]++;
        sol = sol+counter[r[i]];
    }
    g << sol;
    return 0;
}