//horatiu11
# include <cstdio>
# include <vector>
# include <cstring>
# define nmax 100001
using namespace std;
int n,x,y,viz[nmax],L,ultim;
vector <int>G[nmax];
inline void dfs(int x, int niv)
{
    viz[x]=niv;
    for(int i=0;i<G[x].size();++i)
        if(!viz[G[x][i]])
            dfs(G[x][i],niv+1);
    if(viz[x]>L)L=viz[x],ultim=x;
}
int main()
{
    int i;
    freopen("darb.in","r",stdin);
    freopen("darb.out","w",stdout);
    scanf("%d",&n);
    for(i=1;i<n;++i)
    {
        scanf("%d%d",&x,&y);
        G[x].push_back(y);
        G[y].push_back(x);
    }
    dfs(1,1);
    memset(viz,0,sizeof(viz));L=0;
    dfs(ultim,1);
    printf("%d\n",L);
    return 0;
}