#include<cstdio>
#include<vector>
using namespace std;
vector<int> v[100001];
int i,j,n,m,k,vc[100001],vec[100001],qq[100001];
int main ()
{
freopen("darb.in","r",stdin);
freopen("darb.out","w",stdout);
scanf("%d",&n);
for(i=1;i<n;i++)
    {
    int x,y;
    scanf("%d%d",&x,&y);
    v[y].push_back(x);
    v[x].push_back(y);
    }
vc[1]=1;
int in=1,sf=1;
qq[1]=1;
while(sf<n)
    {
    for(i=0;i<v[vc[in]].size();i++)
        if(qq[v[vc[in]][i]]==0)
            {
            qq[v[vc[in]][i]]=1;
            vc[++sf]=v[vc[in]][i];
            }
    in++;
    }
for(i=1;i<=n;i++)
    qq[i]=0;
vc[1]=vc[n];
qq[vc[1]]=1;
in=1;
sf=1;
while(sf<n)
    {
    for(i=0;i<v[vc[in]].size();i++)
        if(qq[v[vc[in]][i]]==0)
            {
            qq[v[vc[in]][i]]=1;
            vc[++sf]=v[vc[in]][i];
            vec[vc[sf]]=vec[vc[in]]+1;
            }
    in++;
    }
printf("%d",vec[vc[n]]+1);
return 0;
}