#include <bits/stdc++.h>
//#include <chrono>
//#pragma GCC optimize("O3")
using namespace std;
#define reps(i,s,n) for(int i = s; i < n; i++)
#define rep(i,n) reps(i,0,n)
#define Rreps(i,n,e) for(int i = n - 1; i >= e; --i)
#define Rrep(i,n) Rreps(i,n,0)
#define ALL(a) a.begin(), a.end()
#define fi first
#define se second

using ll = long long;
using vec = vector<ll>;
using mat = vector<vec>;

ll N, M, K, H, W, A, B, C, D;
string S;
const ll INF = 1LL<<60;

vector<long double> x(300), y(300);

class union_find{
        vector<long> parent, tree_size;
    public:
        union_find(unsigned long _n) : parent(_n), tree_size(_n, 1){
            for(unsigned long i = 0; i < _n; ++i)parent[i] = i;
        }
        ll find(ll x){
            while(parent[x] != x)x = parent[x] = parent[parent[x]];
            return x;
        }
        void merge(ll a, ll b){
            a = find(a);
            b = find(b);
	    if(a==b) return;
            if(tree_size[a] < tree_size[b])swap(a, b);
            tree_size[a] += tree_size[b];
            parent[b] = a;
            return;
        }
	bool same(ll a, ll b){
	    a = find(a);
	    b = find(b);
	    return a == b;
	}
    };
//uf.mergeのように使う
//ufはMAX_N+1でとるか、代入時に0-indexedにする

bool ok(long double r){
    union_find uf(N + 2);
    rep(i, N){
        rep(j, i){
            long double dx = x[i] - x[j], dy = y[i] - y[j];
            if(r * r >= dx * dx + dy * dy){
                uf.merge(i, j);
            }
        }
    }
    rep(i, N/3){
        uf.merge(N, i + N / 3);
        uf.merge(N + 1, i + (N / 3) * 2);
    }
    return !uf.same(N, N + 1);
}

int main(){
    cin>>N;
    cout<<fixed<<setprecision(10);
    rep(i, N){
        cin>>x[i]>>y[i];
        x[i+N] = x[i+N*2] = x[i];
        y[i+N] = -100;
        y[i+N*2] = 100;
    }
    N *= 3;
    long double lb = 0, ub = 200;
    while(ub - lb > 5e-5){
        long double cen = (ub + lb) / 2;
        (ok(cen) ? lb : ub) = cen;
    }
    cout<<lb / 2<<endl;
}

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

#define REP(i,n) for(ll i=0;i<(ll)n;i++)
#define dump(x)  cerr << "Line " << __LINE__ << ": " <<  #x << " = " << (x) << "\n";
#define spa << " " <<
#define fi first
#define se second
#define ALL(a)  (a).begin(),(a).end()
#define ALLR(a)  (a).rbegin(),(a).rend()

using ld = long double;
using ll = long long;
using ull = unsigned long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using pdd = pair<ld, ld>;

template<typename T> using V = vector<T>;
template<typename T> using P = pair<T, T>;
template<typename T> vector<T> make_vec(size_t n, T a) { return vector<T>(n, a); }
template<typename... Ts> auto make_vec(size_t n, Ts... ts) { return vector<decltype(make_vec(ts...))>(n, make_vec(ts...)); }
template<class S, class T> ostream& operator << (ostream& os, const pair<S, T> v){os << "(" << v.first << ", " << v.second << ")"; return os;}
template<typename T> ostream& operator<<(ostream &os, const vector<T> &v) { for (auto &e : v) os << e << ' '; return os; }
template<class T> ostream& operator<<(ostream& os, const vector<vector<T>> &v){ for(auto &e : v){os << e << "\n";} return os;}
struct fast_ios { fast_ios(){ cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; } fast_ios_;

template <class T> void UNIQUE(vector<T> &x) {sort(ALL(x));x.erase(unique(ALL(x)), x.end());}
template<class T> bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T> bool chmin(T &a, const T &b) { if (a>b) { a=b; return 1; } return 0; }
void fail() { cout << -1 << '\n'; exit(0); }
inline int popcount(const int x) { return __builtin_popcount(x); }
inline int popcount(const ll x) { return __builtin_popcountll(x); }
template<typename T> void debug(vector<vector<T>>&v,ll h,ll w){for(ll i=0;i<h;i++)
{cerr<<v[i][0];for(ll j=1;j<w;j++)cerr spa v[i][j];cerr<<"\n";}};
template<typename T> void debug(vector<T>&v,ll n){if(n!=0)cerr<<v[0];
for(ll i=1;i<n;i++)cerr spa v[i];
cerr<<"\n";};

const ll INF = (1ll<<62);
// const ld EPS   = 1e-10;
// const ld PI    = acos(-1.0);
const ll mod = (int)1e9 + 7;
//const ll mod = 998244353;

int main(){

    ll N, M;
    cin >> N >> M;
    V<ll> X(M), Y(M);
    REP(i, M) cin >> X[i] >> Y[i];

    set<ll> st;
    st.insert(N);

    V<ll> ids(M, 0);
    iota(ALL(ids), 0);
    sort(ALL(ids), [&](ll x, ll y){
        return X[x] < X[y];
    });

    REP(i, M){
        ll j = i;
        while(j < M and X[ids[i]] == X[ids[j]]){
            j++;
        }
        ll len = j - i;
        V<ll> check(len, 0);
        V<ll> vals;
        for(ll k=i;k<j;k++){
            vals.push_back(Y[ids[k]]);
        }
        REP(k, len){
            if(st.find(vals[k]-1) != st.end() or st.find(vals[k]+1) != st.end()){
                check[k] = 1;
            }
        }
        REP(k, len){
            if(check[k]){
                st.insert(vals[k]);
            }else{
                auto itr = st.find(vals[k]);
                if(itr != st.end()) st.erase(itr);
            }
        }

        i = j - 1;

        // for(auto x: st) cerr << x << " ";
        // cerr << endl;
    }

    cout << st.size() << endl;

    return 0;
}