#include <bits/stdc++.h>
#define MAX 200001
#define INF LLONG_MAX
#define MOD 1000000007
#define mp make_pair
#define mt make_tuple
#define pb push_back
#define ins insert
#define ff first
#define ss second
#define gett(x,m) get<m>(x)
#define all(a) a.begin(),a.end()
#define lb(a,b) lower_bound(all(a),b)
#define ub(a,b) upper_bound(all(a),b)
#define sortv(a) sort(all(a))
#define sorta(a,sz) sort(a,a+sz)
#define inputar(a,b){\
for(int i=0;i<b;i++){\
cin >> a[i];\
}\
}
#define inputvec(a,b){\
for(int i=0;i<b;i++){\
ll num;\
cin >> num;\
a.pb(num);\
}\
}
#define outputar(a,b){\
for(int i=0;i<b;i++){\
cout << a[i] << " ";\
}\
cout << "\n";\
}
#define outputvec(a){\
for(auto x:a){\
cout << x << " ";\
}\
cout << "\n";\
}
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef tuple<ll,ll,ll> tll;
typedef pair<ll,ll> pll;
typedef double db;
typedef long double ldb;
inline void USACO(string filename){
freopen((filename+".in").c_str(),"r",stdin);
freopen((filename+".out").c_str(),"w",stdout);
}
ll n,q,t=1,m,n2,m2,k,cnt=0,x,y,z,x2,y2,z2,res1=0,a[MAX],b[MAX];
ll c[1501][1501];
ll fact[MAX];
ll inv_fact[MAX];
string str[MAX];
string s1,s2;
const int mod = 998244353;
ll dx[4]={1,0,0,-1};
ll dy[4]={0,1,-1,0};
struct custom_hash {
static uint64_t splitmix64(uint64_t x) {
x += 0x9e3779b97f4a7c15;
x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
return x ^ (x >> 31);
}
size_t operator()(uint64_t x) const {
static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
return splitmix64(x + FIXED_RANDOM);
}
};
vector<ll> used;
vector<vector<ll>> g;
void dfs(ll v){
used[v]=1;
for(auto x:g[v]){
if(used[x]){
continue;
}
dfs(x);
}
}
map<ll,ll> dist;
ll ans(ll rt){
queue<ll> q;
dist.clear();
q.push(rt);
dist[rt]=1;
ll h,h1;
h=rt;
h1=1;
while(!q.empty()){
ll v=q.front();
q.pop();
for(auto x:g[v]){
if(dist[x]!=0){
continue;
}
q.push(x);
dist[x]=dist[v]+1;
if(dist[x]>h1){
h1=dist[x];
h=x;
}
}
}
dist.clear();
q.push(h);
dist[h]=1;
h1=1;
while(!q.empty()){
ll v=q.front();
q.pop();
for(auto x:g[v]){
if(dist[x]!=0){
continue;
}
q.push(x);
dist[x]=dist[v]+1;
if(dist[x]>h1){
h1=dist[x];
h=x;
}
}
}
return h1;
}
void solve(){
cin >> n >> m;
g.resize(n+1);
used.resize(n+1,0);
for(int i=0;i<m;i++){
cin >> x >> y;
g[x].pb(y);
g[y].pb(x);
}
vector<ll> c;
for(int i=1;i<=n;i++){
if(!used[i]){
dfs(i);
c.pb(i);
}
}
ll res=0;
for(auto x:c){
res+=ans(x);
}
cout << res << "\n";
}
int main(){
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
//USACO("poetry");
//freopen("input.txt","r",stdin);
//cin >> t;
ll cnt1=1;
while(t--){
solve();
cnt1++;
}
}
/*
freopen("input.txt","r",stdin);
freopen("output.txt","w",stdout);
ifstream fin("template.in");
ofstream fout("template.out");
*/
/*
freopen("input.txt","r",stdin);
freopen("output.txt","w",stdout);
ifstream fin("template.in");
ofstream fout("template.out");
*/
/*
ll b[51][51];
b[0][0] = 1;
for (int n = 1; n <= 50; ++n){
b[n][0] = b[n][n] = 1;
for (int k = 1; k < n; ++k)
b[n][k] = b[n - 1][k - 1] + b[n - 1][k];
}
*/
