#include <fstream.h>
using namespace std;
ifstream fin("divk.in");
ofstream fout("divk.out");

long x,a,b,n,k,i,v[500002],uz[100002];
long long s;
int main(){

	fin>>n>>k>>a>>b;
	for(i=1;i<=n;i++)
	{
		fin>>x;
		v[i]=(v[i-1]+x)%k;}
	for(i=a;i<=n;i++){
		uz[v[i-a]]++;
		if(i>b)
			uz[v[i-b-1]]--;
		s+=uz[v[i]];}
	fout<<s;
}