#include <fstream>
#include <cstdio>

using namespace std;

int v[524288],w[524288];
long long S;

int main ()
{
	
	ifstream in ("divk.in");
	freopen ("divk.out","w",stdout);
	int n,k,a,b,x;
	in>>n>>k>>a>>b;
	++b;
	for(int i=1;i<=n;++i){
		in>>x;
		v[i]=(x+v[i-1])%k;
		}
	for(int i=a;i<=n;++i){
		++w[v[i-a]];
		if(i>=b)
			--w[v[i-b]];
		S+=w[v[i]];
		}
	printf("%lld",S);
	
	return 0;}