#include<cstdio>
#include<vector>
#include<queue>
#include<cstring>
#define maxN 100001
using namespace std;
FILE *f=fopen("darb.in","r");
FILE *g=fopen("darb.out","w");
vector<int>L[maxN];
queue<int>q;
int ultim,niv[maxN],D,n,m;
bool viz[maxN];
void bfs(int i)
{
    int j,nodcur,vecin;
    memset(viz,false,sizeof(viz));
    memset(niv,0,sizeof(niv));
    q.push(i);
    viz[i]=true;
    niv[i]=1;
    while(!q.empty())
    {
        nodcur=q.front();
        q.pop();
        for(j=0;j<L[nodcur].size();j++)
        {
            vecin=L[nodcur][j];
            if(viz[vecin]==false)
            {
                q.push(vecin);
                niv[vecin]=niv[nodcur]+1;
                D=niv[vecin];
                ultim=vecin;
                viz[vecin]=true;
            }
        }
    }
}
int main()
{
    int i,x,y;
    fscanf(f,"%d",&n);
    for(i=1;i<=n-1;i++)
    {
        fscanf(f,"%d%d",&x,&y);
        L[x].push_back(y);
        L[y].push_back(x);
    }
    bfs(1);
    bfs(ultim);
    fprintf(g,"%d",D);
    return 0;
}