/**
* author: NotLinux
* created: 07.09.2022 ~ 18:41:58
**/
#include <bits/stdc++.h>
using namespace std;
#define int long long
#ifdef LOCAL
#include "/home/notlinux/debug.h"
#else
#define debug(x...) void(37)
#endif
vector < vector < int > > graph;
vector < int > par;
vector < int > vis;
vector < int > visdsu;
pair < int , int > dfs(int node , int past){
pair < int , int > ret = {node,1};
for(auto itr : graph[node]){
if(itr == past)continue;
pair < int , int > dumb = dfs(itr,node);
debug(itr,node,dumb);
if(ret.second < (dumb.second+1)){
ret = {dumb.first , dumb.second+1};
}
}
return {ret.first , ret.second};
}
int longest_path(int st){
debug(st);
int node1 = dfs(st,0).first;
debug(node1);
int rams = dfs(node1,0).second;
debug(st,rams);
return rams;
}
int find(int a){
if(par[a] == a)return a;
par[a] = find(par[a]);
return par[a];
}
void merge(int a, int b){
par[find(a)] = find(b);
}
void solve(){
int n,m;cin >> n >> m;
par.resize(n+1);
iota(par.begin(),par.end(),0LL);
graph.resize(n+1);
vis.resize(n+1);
visdsu.resize(n+1);
while(m--){
int a,b;cin >> a >> b;
graph[a].push_back(b);
graph[b].push_back(a);
merge(a,b);
}
int ans = 0;
for(int i = 1;i<=n;i++){
if(visdsu[find(i)] == 0){
ans += longest_path(i);
visdsu[find(i)] = 1;
}
}
cout << ans << endl;
}
int32_t main(){
ios_base::sync_with_stdio(0);cin.tie(nullptr);
int tt=1;
//cin >> tt;
while(tt--)solve();
}
