#include <cstdio>
#include <algorithm>
#include <vector>
#include <cstring>

#define nmax 100100
#define pb push_back

using namespace std;

vector<int> a[nmax];
bool used[nmax];
int i, n, m, x, y, maxd, nodem;

void dfs(int node, int lvl)
{
    vector<int>::iterator it;

    used[node]=true;

    for(it=a[node].begin(); it!=a[node].end(); it++)
    if(!used[*it]) dfs(*it, lvl+1);

    if(lvl>maxd)
    maxd=lvl, nodem=node;
}

int main()
{
    freopen("darb.in", "rt", stdin);
    freopen("darb.out", "wt", stdout);

    scanf("%d", &n);

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

    dfs(1, 0);
    memset(used, false, sizeof(used));
    dfs(nodem, 0);

    printf("%d", maxd+1);

    return 0;
}