#include <fstream>
using namespace std;

int rest[100005],val[500005];
int n,a,b,k,count,x,ans=0;

int main(){
	ifstream in("divk.in");
	ofstream out("divk.out");

	in>>n>>k>>a>>b;
	for(int i=0;i<n;i++){
		in>>x;
		count=(count+x)%k;
		if(i-a+1>=0)
			rest[val[i-a+1]]++;
		if(i-b>=0)
			rest[val[i-b]]--;
		ans+=rest[count];
		val[i]=count;

	}
	out<<ans;
	return 0;
}