#include <bits/stdc++.h>
using namespace std;
const double EPS = 1e-8;
void fast() {
  std::ios_base::sync_with_stdio(0);
  cin.tie(NULL);
  cout.tie(NULL);
}
bool sortby(const pair<int, int>& a, const pair<int, int>& b) {
  if (a.first >= b.first && a.second >= b.second) return true;
  return false;
}
int arr[1000005];
int main() {
  fast();
  int n;
  double k;
  cin >> n >> k;
  vector<double> v(n);
  for (int i = 0; i < n; i++) {
    cin >> v[i];
  }
  sort(v.begin(), v.end());
  double l = v[0], r = v[n - 1], ans = v[0];
  while (r - l > EPS) {
    double md = (r + l) / 2;
    double sum = 0.00;
    for (int i = 0; i < n; i++) {
      if (v[i] > md)
        sum += ((v[i] - md) - ((v[i] - md) * k / 100));
      else
        sum -= (md - v[i]);
    }
    if (sum >= 0.00) {
      ans = md;
      l = md;
    } else
      r = md;
  }
  cout << setprecision(9) << fixed << ans << endl;
  return 0;
}
