#include <cstdio>
#include <iostream>
#include <set>
#include <climits>
#include <map>
#include <algorithm>
#include <list>
#include <vector>
#include <utility>
#include <cstdlib>
#include <iomanip>
#include <cstring>
#include <string>
#include <cmath>

using namespace std;

int main() {
//    freopen("tt.txt", "r", stdin);
    freopen("divk.in", "r", stdin);
    freopen("divk.out", "w", stdout);

    ios::sync_with_stdio(false);
    cin.tie(0);

    long long ans = 0;
    int n, k, a, b;
    cin >> n >> k >> a >> b;
    int v[500001];
    v[0] = 0;
    for (int i = 1; i <= n; i++) {
        int aux;
        cin >> aux;
        v[i] = (v[i - 1] + aux) % k;
    }
    int total[100000];
    for (int i = 0; i < k; i++) {
        total[i] = 0;
    }
    for (int i = a; i <= n; i++) {
        total[v[i - a]]++;
        ans += total[v[i]];
        if (i >= b)
            total[v[i - b]]--;
    }
    cout << ans;

    return 0;
}