#include <bits/stdc++.h>

using namespace std;

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

int n, k, a, b, v[500007], f[100007], sol;

int main()
{
    fin >> n >> k >> a >> b;
    for (int i = 1; i <= n; ++i)
    {
        fin >> v[i];
        v[i] = (v[i] + v[i - 1]) % k;
        if (i >= a) ++f[v[i - a]];
        if (i > b) --f[v[i - b - 1]];
        sol = sol + f[v[i]];
    }
    fout << sol;
    fin.close();
    fout.close();
}