#include <bits/stdc++.h>

using namespace std;
int n,drum,nodf;
vector <int >g[100005];

void dfs(int ad,int nod,int tata)
{
    if (ad>drum)
    {
        drum=ad;
        nodf=nod;
    }
    for (vector <int > :: iterator it=g[nod].begin();it!=g[nod].end();++it)
        if (*it!=tata)
            dfs(ad+1,*it,nod);
}
int main()
{
    freopen("darb.in","r",stdin);
    freopen("darb.out","w",stdout);
    scanf("%d",&n);
    for (int i=1;i<n;++i)
    {
        int x,y;
        scanf("%d%d",&x,&y);
        g[x].push_back(y);
        g[y].push_back(x);
    }
    dfs(0,1,0);
    dfs(0,nodf,0);
    printf("%d",drum+1);
    return 0;
}