#include <bits/stdc++.h>
using namespace std;

#define mp make_pair
#define pb push_back
#define ll long long int
#define sd(x) scanf("%lld",&x)
#define sdi(x) scanf("%d",&x)
#define sdc(c) scanf("%c",&c)
#define inf 1000000000000000000ll
#define pll pair<ll,ll>
#define pii pair<int,int>
#define fastio ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define bits(x) __builtin_popcountll(x)
#define ld long double
#define test() ll test; cin>>test; while(test--)
#define fi first
#define se second
#define all(x) x.begin(),x.end()


void __print(int x) {cerr << x;}
void __print(long x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(unsigned x) {cerr << x;}
void __print(unsigned long x) {cerr << x;}
void __print(unsigned long long x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}

template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? "," : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifndef ONLINE_JUDGE
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
#define debug(x...)
#endif


inline ll GCD(ll x, ll y) {
    if(x<y) swap(x,y);
    if(x==0) return y;
    if(y==0) return x;
    return GCD(x%y,y);
}

ll phi(ll n) {
    ll result = n;
    for (ll i = 2; i * i <= n; i++) {
        if(n % i == 0) {
            while(n % i == 0)
                n /= i;
            result -= result / i;
        }
    }
    if(n > 1)
        result -= result / n;
    return result;
}

ll power(ll x, ll n, ll mod) {
    ll res = 1;
    x %= mod;
    while(n) {
        if(n&1) {
            res = ((res*x)%mod+mod)%mod;
        }
        x = ((x*x)%mod+mod)%mod;
        n>>=1;
    }

    return res;
}

const int MOD = 1e9+7;

inline ll add(ll x, ll y, ll MOD) {
    x %= MOD;
    y %= MOD;
    ll ans = (x+y)%MOD;
    return ans;
}

inline ll mul(ll x,ll y, ll MOD) {
    x %= MOD;
    y %= MOD;
    ll ans = ((x*y)%MOD+MOD)%MOD;
    return ans;
}

ll N,M;
ll adj[20][20]={0};

int main() {
    fastio;

    cin>>N>>M;

    /*if(M==0) {
        cout<<"N"<<endl;
        return 0;
    }*/

    ll x,y;
    for(int i=1;i<=M;i++) {
        cin>>x>>y;
        adj[x][y] = 1;
        adj[y][x] = 1;
    }

    ll MX = (1<<N);
    ll BT = MX-1;
    vector<ll> v;
    bool check=false;
    vector<ll> dp(MX+1,0);
    dp[0]=1;
    ll ans = 0;
    for(ll i=1;i<MX;i++) {
        // if(bits(i)==1) continue;
        v.clear();
        for(int j=0;j<N;j++) {
            if((i>>j)&1) {
                v.pb(j+1);
            }
        }

        check=true;
        for(int j=0;j<v.size();j++) {
            for(int k=j+1;k<v.size();k++) {
                if(!adj[v[j]][v[k]]) {
                    check=false;
                    break;
                }
            }
        }

        if(check) {
            dp[i] = 1;
        }
    }

    vector<ll> G(MX+1,inf);
    G[0]=0;
    for(ll i=1;i<MX;i++) {
        if(dp[i]) {
            G[i] = 1;
            continue;
        }

        for(ll mask = i;mask>0;mask = (i&(mask-1))) {
            G[i] = min(G[i],G[mask]+G[i^mask]);
        }
    }

    ans = G[BT];
    cout<<ans<<endl;
}



#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
#define all(x) x.begin(),x.end()
#define pll  pair <long long,long long>
#define ss second
#define ff first
#define inf (ll)1e18
#define mod 998244353
#define ld long double
#define fast  ios_base::sync_with_stdio(false);cin.tie(NULL);
#define bug(x) cout << #x <<": " << x << '\n';
#define endl "\n"
#define size sz
const ll N=101 ;
ll n ;
vector<pair<ld,ld>>v ;
vector<ll>adj[N] ;
ld get_dist(ll i,ll j)
{
	return (v[i].ff-v[j].ff)*(v[i].ff-v[j].ff)+(v[i].ss-v[j].ss)*(v[i].ss-v[j].ss) ;
}
bool check(ld r)
{
	ll vis[n] ;
	for(ll i=0;i<n;i++) vis[i]=false ;

	queue<ll>q ;

	for(ll i=0;i<n;i++)
	{
		if(100.0-v[i].ss<2.0*r)
		{
			vis[i]=true ;
			q.push(i) ;
		}
	}

	while(!q.empty())
	{
		ll node=q.front() ;

		if(v[node].ss+100.0<2.0*r) return false ;

		q.pop() ;

		for(ll child:adj[node])
		{
			if(vis[child]==false)
			{
				vis[child]=true ;
				q.push(child) ;
			}
		}
	}
	return true ;
}
int main(){
	fast ;
	cin>>n ;
	for(ll i=0;i<n;i++){
		ld x,y ;
		cin>>x>>y ;
		v.pb({x,y}) ;
	}
	ld low=0.0,high=100.0,ans=1.0 ;
	while((high-low)>=0.000000001){
		ld mid=(low+high)/2.0 ;
		for(ll i=0;i<N;i++) adj[i].clear() ;
		for(ll i=0;i<n;i++){
			for(ll j=i+1;j<n;j++){
				ld dist=get_dist(i,j) ;
				if(dist<4.0*mid*mid) adj[i].pb(j), adj[j].pb(i);
			}
		}
		if(check(mid))  ans=mid,low=mid ;
		else high=mid ;
	}
	cout<<fixed<<setprecision(10)<<ans ;
}
