#include <iostream>
#include <cstdio>
#include <string>
#include <algorithm>

using namespace std;

#define maxN 500005
#define maxK 100005

int v[maxN], nr_rest[maxK], ans;

int main()
{
	freopen ("divk.in", "r", stdin);
	freopen ("divk.out", "w", stdout);
	
	int N, K, A, B;
	
	scanf ("%d %d %d %d", &N, &K, &A, &B);
	
	for (int i = 1; i <= N; ++ i)
	{
		int c;
		
		scanf ("%d", &c);
		
		v[i] = v[i - 1] + c;
		if (v[i] >= K) v[i] %= K;
		
		if (i >= A)
		{
			if (i - A >= 0) ++ nr_rest[v[i - A]];
			if (i - B - 1 >= 0) -- nr_rest[v[i - B - 1]];
			
			ans += nr_rest[v[i]];
		}
	}
	
	printf ("%d", ans);
	
	return 0;
}