#include <cstdio>
#include <vector>
#define NMAX 100001
using namespace std;
FILE* fin=fopen("darb.in","r");
FILE* fout=fopen("darb.out","w");
vector <int> G[NMAX];
int n,uz[NMAX],last,nivmax;
void dfs(int x,int nivel);
int main()
{
    int i,x,y;
    fscanf(fin,"%d",&n);
    for (i=1; i<n; i++)
    {
        fscanf(fin,"%d %d",&x,&y);
        G[x].push_back(y);
        G[y].push_back(x);
    }
    dfs(1,1);
    for (i=1; i<=n; i++) uz[i]=0;
    nivmax=1;
    dfs(last,1);
    fprintf(fout,"%d\n",nivmax);
    return 0;
}
void dfs(int x,int nivel)
{
    int i;
    uz[x]=1;
    if (nivel>nivmax) {nivmax=nivel; last=x;}
    for (i=0; i<G[x].size(); ++i)
    {
        if (!uz[G[x][i]])
        {
            dfs(G[x][i],nivel+1);
        }
    }
}