#include <stdio.h>
#include <iostream>

using namespace std;
	
int main (void) {
	ios_base::sync_with_stdio(false);
	
	freopen("divk.in", "r", stdin);
	freopen("divk.out", "w", stdout);
	
	int v[500005], r[500005], n, k, a, b, x;
	long long sol;
	
	cin >> n >> k >> a >> b;
	
 	r[0] = 1;
	
	for (int i = 1; i <= n; ++i) {
		cin >> x;
		
		v[i] = (v[i - 1] + x) % k;
	}
	
	for (int i = a; i <= n; ++i) {
		sol += r[v[i]];
		++r[v[i - a + 1]];
		if (i >= b) --r[v[i - b]];
	}	
	
	printf("%lld", sol);	
	return 0;
}