#include <fstream>
#include <iostream>
using namespace std;

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

const int MAX_N = 500005;


int n, k, a, b;

int sum[MAX_N];
int frv[100005];

int main() {
    fin >> n >> k >> a >> b;
    int ans = 0;

    for (int i = 1; i <= n; i++) {
        int x;
        fin >> x;
        sum[i] = (1ll * sum[i - 1] + x) % k;
    }

    for (int i = a; i <= n; i++) {
        frv[sum[i - a]]++;

        if (i > b) {
            frv[sum[i - b - 1]]--;
        }
        ans += frv[sum[i]];
    }

    fout << ans << '\n';
}