#include<stdio.h>
long n,a,b,k,v[520000],c[520000];
long long num;
int main() 
{
	long i;
	freopen("divk.in","r",stdin);
	freopen("divk.out","w",stdout);
	scanf("%ld%ld%ld%ld",&n,&k,&a,&b);
	b++;
	for(i=1;i<=n;++i)
	{
		scanf("%ld",&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]]--;
		num=num+(long long)c[v[i]];
	}
	printf("%lld",num);
	return 0;
}