#include <iostream>
#include <fstream>
#define NR 500001


using namespace std;
ifstream fin("divk.in");
ofstream fout("divk.out");
int v[NR],k,a,b,n,div2,f[NR];

void citire()
{
	
	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();
	
	fout<<div2;
	return 0;
}