#include<stdio.h>
#include<algorithm>
#include<cstring>
#include<queue>
#include<vector>
#define pb push_back
#define maxn 100005
using namespace std;

int n,D;
int d[maxn];
vector<int> l[maxn];

void read()
{
    int x,y;
    scanf("%d",&n);
    for(int i=1;i<n;i++)
    {
        scanf("%d%d",&x,&y);
        l[x].pb(y); l[y].pb(x);
    }
}

void bfs(int S)
{
    queue<int> q;
    int k;

    for(d[S]=0,q.push(S);!q.empty();q.pop())
    {
        k=q.front();
        for(unsigned int i=0;i<l[k].size();i++)
         if(!d[l[k][i]])
         {
             d[l[k][i]]=d[k]+1;
             q.push(l[k][i]);
             D=l[k][i];
         }
    }
}

int main()
{
    freopen("darb.in","r",stdin);
    freopen("darb.out","w",stdout);

    read();
    bfs(1);
    memset(d,0,sizeof(d));
    bfs(D);
    printf("%d",d[D]+1);

    fclose(stdin);
    fclose(stdout);
    return 0;
}