#include<bits/stdc++.h>
const int maxn=200001;
inline const void read(int &a)
{
    a=0;
    char c=getchar();
    while(c<'0'||c>'9')c=getchar();
    while(c>='0'&&c<='9')
    {
        a=(a<<1)+(a<<3)+c-'0';
        c=getchar();
    }
}
inline const void write(int a)
{
    if(a>=10)write(a/10);
    putchar(a%10+'0');
}
inline const int max(int a,int b)
{
    if(a>b)return a;
    return b;
}
inline const int min(int a,int b)
{
    if(a<b)return a;
    return b;
}
int point[maxn],n,d=0,ans=0,to[maxn],next[maxn],start,end,dis[maxn];
bool been[maxn],on_chain[maxn];
void dfs1(int p,int tt)
{
    if(tt==1&&dis[p]>dis[start])start=p;
    if(tt==2&&dis[p]>dis[end])end=p;
    been[p]=true;
    int side=point[p];
    while(side)
    {
        if(!been[to[side]])
        {
            dis[to[side]]=dis[p]+1;
            dfs1(to[side],tt);
        }
        side=next[side];
    }
}
bool dfs2(int p)
{
    if(p==end){on_chain[p]=true;return true;}
    been[p]=true;
    int side=point[p];
    while(side)
    {
        if(!been[to[side]])if(dfs2(to[side]))on_chain[p]=true;
        side=next[side];
    }
    if(on_chain[p])return true;
    else return false;
}
void dfs3(int p)
{
    if(on_chain[p])dis[p]=0;
    if(dis[p]>dis[ans])ans=p;
    been[p]=true;
    int side=point[p];
    while(side)
    {
        if(!been[to[side]])
        {
            dis[to[side]]=dis[p]+1;
            dfs3(to[side]);
        }
        side=next[side];
    }
}
inline const void add(int a,int b)
{
    next[++d]=point[a];
    point[a]=d;
    to[d]=b;
}
inline const void init()
{
    memset(dis,0,sizeof(dis));
    memset(been,false,sizeof(been));
}
int main()
{
    //freopen("测试数据.txt","r",stdin);
    memset(on_chain,false,sizeof(on_chain));
    memset(point,0,sizeof(point));
    read(n);
    for(int i=1;i<=n-1;i++)
    {
        int a,b;
        read(a);read(b);
        add(a,b);add(b,a);
    }
    init();
    dfs1(1,1);
    init();
    dfs1(start,2);
    init();
    dfs2(start);
    init();
    dfs3(start);
    write(dis[ans]);
    return 0;
}