#include <iostream>
#include <fstream>

#define NR 500001

using namespace std;
int v[NR],k,a,b,n,f[NR];
long long div2;
void citire()
{
	ifstream fin("divk.in");
	fin>>n>>k>>a>>b;
	for(int i=1;i<=n;i++)
	{
		int x;
		fin>>x;
		v[i]=(v[i-1]+x)%k;
		if(i>=a) ++f[v[i-a]];
		if(i>b) --f[v[i-b-1]];
		div2+=f[v[i]];
	}
}

int main()
{
	citire();
	ofstream fout("divk.out");
	fout<<div2;
	return 0;
}