#pragma GCC optimize ("O3")
#pragma GCC target ("avx")
#include "bits/stdc++.h" // define macro "/D__MAI"

using namespace std;
typedef long long int ll;

#define debugv(v) printf("L%d %s => ",__LINE__,#v);for(auto e:v){cout<<e<<" ";}cout<<endl;
#define debugm(m) printf("L%d %s is..\n",__LINE__,#m);for(auto v:m){for(auto e:v){cout<<e<<" ";}cout<<endl;}
#define debuga(m,w) printf("L%d %s is => ",__LINE__,#m);for(int x=0;x<(w);x++){cout<<(m)[x]<<" ";}cout<<endl;
#define debugaa(m,w,h) printf("L%d %s is..\n",__LINE__,#m);for(int y=0;y<(h);y++){for(int x=0;x<(w);x++){cout<<(m)[x][y]<<" ";}cout<<endl;}
#define debugaar(m,w,h) printf("L%d %s is..\n",__LINE__,#m);for(int y=0;y<(h);y++){for(int x=0;x<(w);x++){cout<<(m)[y][x]<<" ";}cout<<endl;}
#define ALL(v) (v).begin(),(v).end()
#define repeat(l) for(auto cnt=0;cnt<(l);++cnt)
#define iterate(b,e) for(auto cnt=(b);cnt!=(e);++cnt)
#define MD 1000000007ll
#define PI 3.1415926535897932384626433832795
template<typename T1, typename T2>
ostream& operator <<(ostream &o, const pair<T1, T2> p) { o << "(" << p.first << ":" << p.second << ")"; return o; }

#define TIME chrono::system_clock::now()
#define MILLISEC(t) (chrono::duration_cast<chrono::milliseconds>(t).count())
namespace {
    std::chrono::system_clock::time_point ttt;
    void tic() { ttt = TIME; }
    void toc() { fprintf(stderr, "TIME : %lldms\n", MILLISEC(TIME - ttt)); }
    std::chrono::system_clock::time_point tle = TIME;
#ifdef __MAI
    void safe_tle(int msec) { assert(MILLISEC(TIME - tle) < msec); }
#else
#define safe_tle(k) ;
#endif
}

#ifdef __MAI
#define getchar_unlocked getchar
#define putchar_unlocked putchar
#endif
#ifdef __VSCC
#define getchar_unlocked _getchar_nolock
#define putchar_unlocked _putchar_nolock
#endif
namespace {
#define isvisiablechar(c) (0x21<=(c)&&(c)<=0x7E)
    class MaiScanner {
    public:
        template<typename T>
        void input_integer(T& var) {
            var = 0;
            T sign = 1;
            int cc = getchar_unlocked();
            for (; cc<'0' || '9'<cc; cc = getchar_unlocked())
                if (cc == '-') sign = -1;
            for (; '0' <= cc&&cc <= '9'; cc = getchar_unlocked())
                var = (var << 3) + (var << 1) + cc - '0';
            var = var*sign;
        }
        inline int c() { return getchar_unlocked(); }
        inline MaiScanner& operator>>(int& var) {
            input_integer<int>(var);
            return *this;
        }
        inline MaiScanner& operator>>(long long& var) {
            input_integer<long long>(var);
            return *this;
        }
        inline MaiScanner& operator>>(string& var) {
            int cc = getchar_unlocked();
            for (; !isvisiablechar(cc); cc = getchar_unlocked());
            for (; isvisiablechar(cc); cc = getchar_unlocked())
                var.push_back(cc);
        }
    };
}
MaiScanner scanner;



class qunionfind {
public:
    vector<vector<int>> toItems;
    vector<int> data;

    qunionfind(int size) : data(size, -1) {
        toItems.resize(size);
        for (int i = 0; i<size; i++) {
            toItems[i].emplace_back(i);
        }
    }
    bool union_set(int x, int y) {
        x = root(x); y = root(y);
        if (x != y) {
            if (data[y] < data[x]) swap(x, y);
            toItems[x].insert(toItems[x].end(), ALL(toItems[y]));
            data[x] += data[y]; data[y] = x;
        }
        return x != y;
    }
    inline bool find_set(int x, int y) {
        return root(x) == root(y);
    }
    inline int root(int x) {
        return data[x] < 0 ? x : data[x] = root(data[x]);
    }
    inline int size(int x) {
        return -data[root(x)];
    }
};


int n;
ll pos[1010][2];

inline ll hypo(ll x, ll y) { return x*x + y*y; }

int main() {

    scanner >> n;
    if (n == 0) {
        cout << 1 << endl;
        return 0;
    }
    repeat(n) {
        int x, y;
        scanner >> x >> y;
        pos[cnt][0] = x;
        pos[cnt][1] = y;
    }

    // vector<pair<double, int>> edges;
    // edges.reserve(n*(n + 1) / 2 + 10);

    qunionfind uf(n);

    for (int i = 0; i < n-1; ++i) {
        ll x = pos[i][0];
        ll y = pos[i][1];
        for (int j = i+1; j < n; ++j) {
            if (hypo(x - pos[j][0], y - pos[j][1]) <= 100) {
                uf.union_set(i, j);
            }
        }
    }

    ll best = 0;
    vector<int> visit(n);

    for (int t = 0; t < n; ++t) {
        int head = uf.root(t);
        if (visit[head]) continue;
        visit[head] = 1;
        const vector<int>& items = uf.toItems[head];
        int m = items.size();
        for (int i = 0; i < m - 1; ++i) {
            for (int j = 1 + i; j < m; ++j) {
                best = max(hypo(pos[items[i]][0] - pos[items[j]][0], pos[items[i]][1] - pos[items[j]][1]), best);
            }
        }
    }
    printf("%.10f\n", sqrt(best) + 2);


    return 0;
}