#include<stdio.h>
int v[500005],d[500005];
int main()
{
	freopen("divk.in","r",stdin);
	freopen("divk.out","w",stdout);
	int n,i,k,a,b;long long s=0;
	scanf("%d%d%d%d",&n,&k,&a,&b);
	for(i=1;i<=n;i++)
	{
		scanf("%d",&v[i]);
		v[i]=(v[i]+v[i-1])%k;
	}
	for(i=a;i<=n;i++)
	{
		d[v[i-a]]++;
		if(i>b) 
			d[v[i-b-1]]--;
		s=s+d[v[i]];
	}
	printf("%lld\n",s);
	return 0;
}