#include <fstream>
using namespace std;

long long rest[100005],val[500005];
long long 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=1;i<=n;i++){
		in>>x;
		count=(count+x)%k;
		val[i]=count;
		if((i-a)>=0)
			rest[val[i-a]]++;
		if((i-b-1)>=0)
			rest[val[i-b-1]]--;
		if(rest[count]!=0)
			out<<"";
		ans+=rest[count];

	}
	out<<ans;
	return 0;
}