#include<cstdio>
const int nmax=1<<19,lmax=1<<17;;
int sol,x,n,k,A,B,s[nmax],v[lmax];
int main()
{
	freopen("divk.in","r",stdin);
	freopen("divk.out","w",stdout);
	scanf("%d%d%d%d",&n,&k,&A,&B);
	for(int i=1;i<=n;i++)
	{
		scanf("%d",&x);
		s[i]=(s[i-1]+x)%k;
	}
	for(int i=1;i<=A-1;i++)
		v[s[i]]++;
	for(int i=A;i<=n;i++)
	{
		sol+=v[s[i]];
		if(i-B>0)
			v[s[i-B]]--;
		v[s[i-A+2]]++;
	}
	printf("%d",sol);
	return 0;
}