#include<stdio.h>
#include<stdlib.h>
#define N 100001
int i,n,c[N],l,d,a[N],b[N],w[N],*g[N],o[5*N],p,u;
void B(int t)
{
	int i,k;
    for(i=1;i<=n;++i)
        c[i]=0;
    for(o[u++]=t,c[t]=1;p<u;++p)
    	for(k=o[p],i=0;i<w[k];++i)
    		if(!c[g[k][i]])
        		l=g[k][i],o[u++]=l,c[l]=c[k]+1,d=c[l];
}
int main()
{
    freopen("darb.in","r",stdin),freopen("darb.out","w",stdout),scanf("%d",&n);
    for(i=0;i<n-1;++i)
        scanf("%d%d",a+i,b+i),w[a[i]]++,w[b[i]]++;
    for(i=1;i<=n;w[i++]=0)
        g[i]=(int*)malloc(4*w[i]);
    for(i=0;i<n-1;++i)
        g[a[i]][w[a[i]]++]=b[i],g[b[i]][w[b[i]]++]=a[i];
    B(1),B(l),printf("%d",d);
}