#include<bits/stdc++.h>
#include<queue>
using namespace std;
 
#define what_is(x) cout << #x << " is " << x << endl; 
#define PI acos(-1)
#define hell 1000000007
#define HELL 998244353
#define io ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0)
#define fix(n) cout << fixed << setprecision(n)
#define mset(a,n) memset(a,n,sizeof a)
#define rep(i,a,b) for (__typeof((b)) i=(a);i<(b);i++)
#define repp(i,a,b,p) for(__typeof((b)) i=(a);i<(b);i+=p)
#define ren(i,a,b) for(__typeof((a)) i=(a);i>=(b);i--)
#define renn(i,a,b,p) for(__typeof((a) i=(a);i>=(b);i-=p)
#define ADD(a,b,c) ((a)%c+(b)%c)%c
#define SUB(a,b,c) ((a)%c-(b)%c+c)%c
#define MUL(a,b,c) (((a)%c)*((b)%c))%c
#define lbd lower_bound
#define ubd upper_bound
#define ll long long
#define ld long double
#define pb push_back
#define fi first
#define se second
#define vll vector<ll>
#define pll pair<ll,ll>
#define vpll vector<pll>
#define all(v) (v).begin(), (v).end()
#define sz(x) (ll)x.size()
// #define out(n) cout<<n<<" "
#define outl(n) cout<<n<<endl
#define bug(n) {outl(n);return;}
#define pii pair<int,int>
#define lim 9223372036854775805
#define ninf -9223372036854775802
#define M 1000000007
#define eps 1e-6
#define MAX 5
#define N 500001
#define db(a) for(auto it:a) {cout<<it<<" ";}cout<<endl;
ll prime[MAX]; 
ll fact[MAX];

const long long INF64 = 1e18;
ll vpow(ll a,ll b,ll p){
    if(b==0)
        return 1;
    if(b==1)
            return a;
    ll temp=vpow(a,b/2,p);
    temp*=temp;
    temp%=p;
    if(b%2==0)
        return temp;
    temp=temp*a;
    temp%=p;
    return temp;
}

ll gcd(ll a,ll b){
     if(a==0)
         return b;
     return gcd(b%a,a);
 }

 
ll inverseMod(ll a,ll b,ll p){
    if(b==0)
        return 1;
    ll temp=vpow(b,p-2,p);
    ll ans=temp*a;
    ans%=p;
    return ans;
}
void sieve() 
{ 
    prime[0] = prime[1] = 1; 
    for (ll i = 2; i < MAX; i++) { 
        if (prime[i] == 0) {
            for (int j = i * 2; j < MAX; j += i) { 
                if (prime[j] == 0) { 
                    prime[j] = i; 
                } 
            } 
            prime[i] = i; 
        } 
    } 
}

void factorial(){
    fact[0]=1;
    fact[1]=1;
    rep(i,2,MAX){
        fact[i]=(fact[i-1]*i);
        // fact[i]%=M;
    }
}
// string s="689";
// // string ans="";
// // string rec(vll &power,ll lvl,ll n,ll tot){
// // 	if(tot+power[lvl]>=n){
// // 		return (string)""+s[(n-tot)/(power[lvl-1])]+rec(power,lvl-1,)
// // 	}
// // 	n%=power[lvl];

// // }
// string recc(ll n){
// 	if(n==0)
// 		return "";
// 	n--;
// 	if(n<3)
// 		return (string )""+s[n];

// 	return (string )""+s[n%3]+recc(n/3);
// }

ll dfs(vll adj[],ll u,vector<bool>&vis){
	vis[u]=true;
	ll cnt=1;
	for(auto ch:adj[u]){
		if(!vis[ch]){
			cnt+=dfs(adj,ch,vis);
		}
	}
	return cnt;
}
void solve(ll ttt){
	ll n,m;
	cin>>n>>m;
	vll adj[n];
	rep(i,0,m){
		ll a,b;
		cin>>a>>b;
		a--;b--;
		adj[a].pb(b);
		adj[b].pb(a);
	}
	vll a;
	vector<bool> vis(n,false);
	rep(i,0,n){
		if(!vis[i]){
			ll cnt=dfs(adj,i,vis);
			a.pb(cnt);
		}
	}
	ll ans=0;
	sort(all(a));
	ll prev=0;
	rep(i,0,sz(a)){
		int now=a[i];
		ll cnt=a[i];
		while(i<sz(a) && a[i]==now){
			i++;
		}
		i--;
		ans+=now-prev;
		prev+=(now-prev);
	}
	cout<<ans<<endl;
}

int main(){
    io;
   
    // sieve();
    // factorial();
#ifndef ONLINE_JUDGE
    freopen("input1.txt","r",stdin);
    //freopen("output1.txt","w",stdout);
#endif
    ll t=1;
    // cin>>t;
    fix(12);
    rep(q,1,t+1){
        // cout<<"Case #"<<q<<": ";
         solve(q);
        //solve2();
    }
    return 0;
    
}


Measured memory_bytes: 27124