#include <cstdio>
#include <vector>
#define N 100010
using namespace std;
int n,i,x,y,g[N],d[N];
vector <int> v[N],Q;
int main()
{
    freopen("darb.in","r",stdin);
    freopen("darb.out","w",stdout);
    scanf("%d",&n);
    for(i=1;i<n;i++)
    {
        scanf("%d%d",&x,&y);
        v[x].push_back(y);
        v[y].push_back(x);
        g[x]++;
        g[y]++;
    }
    for(i=1;i<=n;i++)
        if(g[i]==1)
        {
            Q.push_back(i);
            d[i]=1;
        }
    for(i=0;i<n;i++)
    {
        x=Q[i];
        for(vector<int>::iterator it=v[x].begin();it!=v[x].end();it++)
            if(g[*it]>1)
            {
                g[*it]--;
                if(g[*it]==1)
                {
                    d[*it]=d[x]+1;
                    Q.push_back(*it);
                }
            }
    }
    printf("%d\n",d[Q[n-2]]+d[Q[n-1]]);
    return 0;
}