#include<stdio.h>
long n,k,a,b,ap[10000007],s[500007],v[500007],sum,i;
int main()
{
	freopen("divk.in","r",stdin);
	freopen("divk.out","w",stdout);
	scanf("%ld %ld %ld %ld",&n,&k,&a,&b);
	for (i=1;i<=n;i++)
		scanf("%ld",&v[i]);
	for (i=1;i<=n;i++)
		s[i]=(s[i-1]+v[i])%k;
	for(i=1;i<=n;i++)
    {
		if(i-a>=0)
          ++ap[s[i-a]];
		if(i-b>0)
          --ap[s[i-b-1]];
		sum+=ap[s[i]];
    }
	printf("%ld",sum);
}