Codeforces Beta Round #87 (Div. 2 Only) C. Party

# include <stdio.h>
int main ()
{
int i,m,n,sum,max=1,q;
int a[2005];
scanf("%d",&n);
for(i=1;i<=n;i++)
{
scanf("%d",&a[i]);
}
for(i=1;i<=n;i++)
{
//	printf("%d  ",i);
sum=1;
q=a[i];
while(q!=-1)
{
q=a[q];
sum++;
}
if(sum>max)
max=sum;
}
printf("%d\n",max);
return 0;
}