#include <bits/stdc++.h>
using namespace std;
const int N = 1e5+10;
struct info{
int len, node;
info(int _len, int _node): len(_len), node(_node){};
info(): len(1), node(0){};
} dp[N];
bool vis[N];
vector<int> adj[N];
void dfs(int u, int p){
vis[u] = 1;
dp[u] = info(1, u);
for(int v : adj[u]) if(v != p){
dfs(v, u);
if(dp[u].len < dp[v].len+1){
dp[u] = {dp[v].len+1, dp[v].node};
}
}
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int n, m;
cin >> n >> m;
while(m--){
int u, v;
cin >> u >> v;
adj[u].push_back(v);
adj[v].push_back(u);
}
int res = 0;
for(int i = 1; i <= n; ++i){
if(vis[i]) continue;
dfs(i, -1);
int farthest = dp[i].node;
dfs(farthest, -1);
res += dp[farthest].len;
}
cout << res << '\n';
}
