#include <bits/stdc++.h>
using namespace std;
ifstream f("divk.in");
ofstream g("divk.out");

int n, k, a, b, v[500005], fr[100005];
long long ans = 0;

int main()
{
    f >> n >> k >> a >> b;
    v[0] = 0;
    fr[0] = 0;
    for (int i=1; i<=n; ++i) {
        f >> v[i];
        v[i] = (v[i-1] + v[i]) % k;
        if (i >= b + 1)
            fr [v[i-b-1]] --;
        if (i >= a)
            fr [v[i-a]] ++;
        ans += fr[v[i]];
    }
    g << ans;
    return 0;
}