#include <cstdio>
#include <vector>
using namespace std;
FILE *f,*g;

vector <int> a[100100];
int i,n,x,y,mx,mxi;
int bf[100100];

void dfs(int x,int ind)
{
    int i;

    bf[x]=ind;
    if (ind>mx)
    {
        mx=ind;
        mxi=x;
    }

    for (i=0;i<a[x].size();i++)
        if (bf[a[x][i]]==0)
            dfs(a[x][i],ind+1);
}

int main()
{
    f=fopen("darb.in","r");
    g=fopen("darb.out","w");

    fscanf(f,"%d",&n);
    for (i=1;i<n;i++)
    {
        fscanf(f,"%d%d",&x,&y);
        a[x].push_back(y);
        a[y].push_back(x);
    }

    mx=0;
    dfs(1,1);
    for (i=1;i<=n;i++) bf[i]=0;
    dfs(mxi,1);

    fprintf(g,"%d",mx);

}