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