#include<fstream>

#define NMAX 500005
#define KMAX 100005

using namespace std;

ifstream fin("divk.in");
ofstream fout("divk.out");

int n,k,a,b,apar[KMAX],v[NMAX];
long long sol;

int main()
{
	fin>>n>>k>>a>>b;
	for(int i=1;i<=n;i++)
	{
		fin>>v[i];
		v[i]=(v[i]+v[i-1])%k;
	}
	for(int i=a;i<=n;i++)
	{
		apar[v[i-a]]++;
		if(i>b)
			apar[v[i-b-1]]--;
		sol+=apar[v[i]];
	}
	fout<<sol;
	return 0;
}