#include <bits/stdc++.h>
using namespace std;
#define nl '\n'
typedef long long ll;
const int MAXN = 1e5+5;
int n,m;
vector<int> graph[MAXN];
bool visited[MAXN];
int dist[MAXN];
void dfsMark(int u) {
visited[u] = true;
for (int v : graph[u]) {
if(!visited[v]) dfsMark(v);
}
}
void dfsDist(int u, int pre) {
for (int v : graph[u]) {
if(v != pre) {
dist[v] = dist[u] + 1;
dfsDist(v,u);
}
}
}
int calcDiameter(int start) {
fill(dist, dist+n+1, -1);
dist[start] = 0;
dfsDist(start,-1);
int far = start;
for (int i=1; i<=n; i++) {
if(dist[i] > dist[far]) far = i;
}
fill(dist, dist+n+1, -1);
dist[far] = 0;
dfsDist(far,-1);
int diam = 0;
for (int i=1; i<=n; i++) {
diam = max(diam, dist[i]);
}
return diam+1;
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cin >> n >> m;
for (int i=1; i<=m; i++) {
int u,v; cin >> u >> v;
graph[u].push_back(v);
graph[v].push_back(u);
}
ll res = 0;
fill(visited, visited+n+1, false);
for (int i=1; i<=n; i++) {
if(!visited[i]) {
dfsMark(i);
res += calcDiameter(i);
}
}
cout << res << nl;
}
