#include<stdio.h>
int n,k,a,b,v[5002],f[1002];
int main()
{
	freopen("divk.in","r",stdin);
	freopen("divk.out","w",stdout);
	scanf("%d%d%d%d",&n,&k,&a,&b);
	int i,sol=0;
	for(i=1;i<=n;i++)
	{
		scanf("%d",&v[i]);
		v[i]+=v[i-1];
	}
	for(i=a;i<=n;i++)
	{
		if(i>b)
			f[v[i-b]%k]--;
		f[v[i-a+1]%k]++;
		sol=sol+f[v[i]%k];
	}
	printf("%d",sol);
	return 0;
}