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

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);

  int n;
  cin >> n;
  vector<pair<int, int>> pos(n);
  for (auto &&[x, y] : pos) {
    cin >> x >> y;
  }
  auto judge = [&](double r) -> bool {
    queue<int> q;
    for (auto i = 0; i != n; ++i) {
      if (100 - r < pos[i].second + r) {
        q.push(i);
      }
    }
    vector<bool> used(n);
    while (!q.empty()) {
      auto id = q.front();
      q.pop();
      if (used[id]) continue;
      used[id] = true;
      for (auto i = 0; i != n; ++i) {
        if (hypot(pos[i].first - pos[id].first,
                  pos[i].second - pos[id].second) < 2 * r) {
          q.push(i);
        }
      }
    }
    for (auto i = 0; i != n; ++i) {
      if (used[i]) {
        if (r - 100 > pos[i].second - r) {
          return false;
        }
      }
    }
    return true;
  };
  constexpr double eps = 1e-4;
  double ok = 0, ng = 100;
  while (ng - ok > eps) {
    auto r = (ok + ng) / 2;
    if (judge(r))
      ok = r;
    else
      ng = r;
  }
  cout << ok << endl;
}

#include              <bits/stdc++.h>
#define ll            long long int
#define w(t)          int t; cin>>t; while(t--)
#define F             first
#define S             second
#define pb            push_back
#define mp            make_pair
#define pii           pair<int,int>
#define mii           map<int,int>
#define sp(x,y)       fixed<<setprecision(y)<<x
using namespace std;

// ll modular(ll base, unsigned long long int exp, unsigned int mod)
// {
//     ll x = 1;
//     ll power = base % mod;

//     for (ll i = 0; i < sizeof(long long int) * 8; i++) {
//         ll least_sig_bit = 0x00000001 & (exp >> i);
//         if (least_sig_bit)
//             x = (x * power) % mod;
//         power = (power * power) % mod;
//     }

//     return x;
// }
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    // ll a,b,c;
    // cin>>a>>b>>c;
    // if(modular(a,c,1000000007)==modular(b,c,1000000007))cout<<"=";
    // else if(modular(a,c,1000000007)<modular(b,c,1000000007))cout<<"<";
    // else if(modular(a,c,1000000007)>modular(b,c,1000000007))cout<<">";
    // return 0;
    float a,b;
    cin>>a>>b;
    float ans=b/100;
    ans*=a;
    cout<<ans;
    return 0;
}