#include<stdio.h>
#include<vector>
using namespace std;
#define nmax 100005
int x, y, inc, sf, n, m, i;
vector <int> ma[nmax];
vector <int> ::iterator it;
int co[nmax], dist[nmax];

void citire()
{
    scanf("%ld",&n);
    for (i=1;i<=n-1;i++)
    {
        scanf("%ld %ld",&x,&y);
        ma[x].push_back(y);
        ma[y].push_back(x);
    }
}

void bfs(int s)
{
    for (i=1;i<=n;i++)
        dist[i]=0;
    inc=sf=1;
    co[1]=s;    dist[s]=1;
    while (inc<=sf)
    {
        x=co[inc];  inc++;
        for (it=ma[x].begin();it!=ma[x].end();it++)
            if (dist[*it]==0)
            {
                dist[*it]=dist[x]+1;
                co[++sf]=*it;
            }
    }
}

int main()
{
    freopen("darb.in","r",stdin);
    freopen("darb.out","w",stdout);
    citire();
    bfs(1);
    bfs(co[sf]);
    printf("%ld",dist[co[sf]]);
    return 0;
}