#include<cstdio>
#include<vector>
#include<cstring>
using namespace std;
#define NMAX 100005
vector <int> v[NMAX];
int n,x,y,L,u,a[NMAX];
void dfs(int s, int niv)
{
    int i;
    a[s]=niv;
    for (i=0;i<v[s].size();++i)
        if (!a[v[s][i]])
            dfs(v[s][i],niv+1);
    if (a[s]>L) L=a[s], u=s;
}
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);
        v[x].push_back(y);
        v[y].push_back(x);
    }
    dfs(1,1);
    memset(a,0,sizeof(a));
    L=0;
    dfs(u,1);
    printf("%d\n",L);
    return 0;
}