#include<fstream>
using namespace std;
int n,i,j,k,A,B,x;
unsigned long long uz[500001],a[500001],m;
int main()
{
	freopen("divk.in","r",stdin);
	freopen("divk.out","w",stdout);
	scanf("%d%d%d%d",&n,&k,&A,&B);
	for(i=1;i<=n;++i)
	{
		scanf("%d",&x);
		a[i]=(a[i-1]+x)%k;
	}
	for(i=A;i<=n;++i)
	{
			++uz[a[i-A]];
		if(i>B)
			--uz[a[i-B-1]];
		m+=uz[a[i]];
	}
	printf("%lld",m);
	return 0;
}