#include<fstream>
using namespace std;
int v[500007],s[500005],n,a,b,k,caract[500005];
long long rez;
int main()
{
	ifstream fin("divk.in");
	ofstream fout("divk.out");
	fin>>n>>k>>a>>b;
	int i;
	for(i=1;i<=n;i++)
		fin>>v[i],s[i]=(s[i-1]+v[i])%k;
	++b;
	for(i=a;i<=n;i++)
	{	
		caract[s[i-a]]++;
	    if(i>=b)
			caract[s[i-b]]--;
		rez+=caract[s[i]];
	}
	fout<<rez;
	return 0;
}