#include<fstream>
#include<cstdio>
#include<set>
#include<stack>
#include<vector>
#include<algorithm>
#define FOR(a,b,c) for(int a=b;a<=c;++a)
#include<cstring>
#include<bitset>
#include<cmath>
#include<iomanip>
#include<queue>
#define f cin
#define g cout
#define mp make_pair
#define pb push_back
#define ll long long
#define inf (1<<30)
#define base 256
#define ba 255
#define N 1000100
#define EPS 1e-12
#define mod  98999
#define inu "darb.in"
#define outu "darb.out"
using namespace std;
ifstream f(inu);
ofstream g(outu);
//int dx[]={0,0,0,1,-1};
//int dy[]={0,1,-1,0,0};
vector<int> v[N];
int n,m,dis,x,y,dist,nm;
void dfs(int x,int dad)
{
	++dis;
	if(dis>dist)
	{
		dist=dis;
		nm=x;
	}
	for(int i=0;i<v[x].size();++i)
		if(v[x][i]!=dad)
			dfs(v[x][i],x);
	--dis;
}
int main ()
{
	f>>n;
	FOR(i,1,n-1)
	{
		f>>x>>y;
		v[x].pb(y);
		v[y].pb(x);
	}
	dfs(1,0);
	dfs(nm,0);
	g<<dist;
    return 0;
}