#include <cstdio>
#include <vector>
#include <algorithm>
#include <deque>
#include <utility>
#include <queue>
using namespace std;
typedef pair<int,int> pi;
int n;
vector<int> graph[200005];
int low[200005], dfn[200005], piv;
int is_cyc[200005];
void dfs(int x, int pa){
low[x] = dfn[x] = ++piv;
for (int i=0; i<graph[x].size(); i++) {
if(graph[x][i] == pa) continue;
if(dfn[graph[x][i]]){
is_cyc[graph[x][i]] = 1;
low[x] = min(low[x],dfn[graph[x][i]]);
}
else{
dfs(graph[x][i],x);
low[x] = min(low[x],low[graph[x][i]]);
}
}
if(low[x] < dfn[x]) is_cyc[x] = 1;
}
pi bfs(int x){
queue<int> q,p,dist;
q.push(x);
p.push(0);
dist.push(0);
pi ret(0ll,0);
while (!q.empty()) {
int qf = q.front();
int pf = p.front();
int df = dist.front();
q.pop();
p.pop();
dist.pop();
ret = max(ret,pi(df,qf));
for (int i=0; i<graph[qf].size(); i++) {
int pos = graph[qf][i];
if(is_cyc[pos] || pos == pf) continue;
q.push(pos);
p.push(qf);
dist.push(df+1);
}
}
return ret;
}
int nxt[200005], far[200005], bef[200005];
void solve(){
int start_pos = 0, ret = 0, cnt = 0;
for (int i=1; i<=n; i++) {
if(is_cyc[i]) start_pos = i, cnt++;
}
int pos = start_pos, par = 0;
int size = 0;
do{
is_cyc[pos] = 0;
pi x = bfs(pos);
far[pos] = x.first;
ret = max(ret,bfs(x.second).first);
is_cyc[pos] = 1;
for (int i=0; i<graph[pos].size(); i++) {
if(graph[pos][i] == par) continue;
if(is_cyc[graph[pos][i]]){
nxt[pos] = graph[pos][i];
par = pos;
pos = nxt[pos];
bef[pos] = par;
break;
}
}
size++;
}while (pos != start_pos);
do{
int pos2 = nxt[pos], i = 1;
while (pos2 != pos) {
ret = max(ret,far[pos] + far[pos2] + min(i,cnt-i));
i++;
pos2 = nxt[pos2];
}
pos = nxt[pos];
}while (pos != start_pos);
printf("%d",ret);
}
int main(){
scanf("%d",&n);
for (int i=0; i<n; i++) {
int x,y;
scanf("%d %d",&x,&y);
graph[x].push_back(y);
graph[y].push_back(x);
}
dfs(1,0);
solve();
}
