#include<cstdio>
#include<vector>
#include<queue>
#include<cstring>
#define nmax 100002
using namespace std;
vector <int> v[nmax];
queue <int> q;
int viz[nmax];
int bfs(int x)
{
    memset(viz,0,sizeof(viz));
    q.push(x);
    viz[x]=1;
    int maxim=x;
    while(!q.empty())
    {
        int y=q.front();

        for(int i=0;i<v[y].size();i++)
        {
            int z=v[y][i];
            if(viz[z]==0)
            {
                q.push(z);
                viz[z]=1+viz[y];
                if(viz[z]>viz[maxim])
                    maxim=z;
            }
        }
        q.pop();
    }
    return maxim;
}
int main()
{
    freopen("darb.in","r",stdin);
    freopen("darb.out","w",stdout);
    int x,y,i,n;
    scanf("%d",&n);
    for(i=1;i<n;i++)
    {
        scanf("%d %d",&x,&y);
        v[x].push_back(y);
        v[y].push_back(x);
    }
    int drum=bfs(bfs(1));
    printf("%d",viz[drum]);
    return 0;
}