#include<bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
#define int long long
typedef pair<int,int> pii;
typedef vector<pii> vii;
typedef vector<int> vi;
#define FOR(i,a) for(int i=0;i<(a);i++)
#define FORE(i,a,b) for(int i=(a);i<(b);i++)
#define all(x) x.begin(),x.end()
#define fi first
#define se second
#define pb push_back
#define sp <<" "<<
#define cont(x) for(auto el:x) cout<<el<<' ';cout<<endl;
#define contp(x) for(auto el:x) cout<<el.fi<<'-'<<el.se<<' ';cout<<endl;
#define DEBUG(x) cout<<#x sp x<<endl;
#define carp(x,y) ((x%MOD)*(y%MOD))%MOD
#define topla(x,y) ((x%MOD)+(y%MOD))%MOD
#define mid (l+r)/2
const int MAXN=2e5+5;
const int INF=1e18;
vi adj[MAXN];
int vis[MAXN];
int mx;
int tut;
int cur;
void dfs(int nd,int h){
vis[nd]=cur;
if(h>mx){
mx=h;
tut=nd;
}
for(auto kom:adj[nd]){
if(vis[kom]==cur) continue;
dfs(kom,h+1);
}
}
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(0);
int n,m;
cin>>n>>m;
FOR(i,m){
int a,b;
cin>>a>>b;
adj[a].pb(b);
adj[b].pb(a);
}
int cev=0;
cur=0;
FORE(i,1,n+1){
if(!vis[i]){
cur++;
mx=tut=-1;
dfs(i,0);
cur++;
dfs(tut,0);
cev+=mx+1;
}
}
cout<<cev<<endl;
}
