#include <stdio.h>
#include <vector>
using namespace std;
vector<unsigned> graf[100002];
long n,i,nod,x,y,m;
bool viz[100002];
void dfs(long x, long dist)
{
    viz[x]=true;
    if(dist>m)
    {
        m=dist;
        nod=x;
    }
    for(int i=0;i<graf[x].size();i++)
        if(!viz[graf[x][i]])
            dfs(graf[x][i],dist+1);
}
int main()
{
    FILE *f1,*f2;
    f1=fopen("darb.in","r");
    f2=fopen("darb.out","w");
    fscanf(f1,"%ld",&n);
    for(i=1;i<n;i++)
    {
        fscanf(f1,"%ld%ld",&x,&y);
        graf[x].push_back(y);
        graf[y].push_back(x);
    }
    dfs(1,1);
    for(i=1;i<=n;i++)
        viz[i]=false;
    dfs(nod,1);
    fprintf(f2,"%ld",m);
    return 0;
}