#include <fstream>
#include <string>
#include <algorithm>

using namespace std;

#define maxN 500005
#define maxK 100005
#define LL long long

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

int main()
{
	ifstream f ("divk.in");
	ofstream g ("divk.out");
	
	int N, K, A, B;
	
	f >> N >> K >> A >> B;
	
	for (int i = 1; i <= N; ++ i)
	{
		int c;
		
		f >> c;
		
		v[i] = (v[i - 1] + c) % K;
		
		if (i >= A)
		{
			++ nr_rest[v[i - A]];
			if (i - B - 1 >= 0) -- nr_rest[v[i - B - 1]];
			
			ans += (LL) nr_rest[v[i]];
		}
	}
	
	g << ans;
	
	return 0;
}