#include <cstdio>
#include <vector>

using namespace std;

int nivmax,nod1;
vector<int> v[100010];

void dfs(int nod,int nivel,int tata)
{
    if(nivel>nivmax) {nivmax=nivel;nod1=nod;}
    for(int i=0;i<v[nod].size();i++)
        if(v[nod][i]!=tata) dfs(v[nod][i],nivel+1,nod);
}

int main()
{
    freopen("darb.in","r",stdin);
    freopen("darb.out","w",stdout);
    int n,x,y;
    scanf("%d",&n);
    for(int i=1;i<n;i++)
    {
        scanf("%d%d",&x,&y);
        v[x].push_back(y);
        v[y].push_back(x);
    }
    dfs(1,1,0);
    nivmax=0;
    dfs(nod1,1,0);
    printf("%d",nivmax);
    return 0;
}