#include <bits/stdc++.h>
using namespace std;
int main() {
  double n, k;
  cin >> n >> k;
  vector<double> v(n);
  for (int i = 0; i < n; ++i) cin >> v[i];
  double l = 0., r = 2000., mid;
  while (r - l >= 0.00000001) {
    mid = (r + l) / 2;
    double sum_min = 0, sum_pl = 0;
    for (int i = 0; i < v.size(); ++i) {
      if (v[i] > mid)
        sum_min += v[i] - mid;
      else
        sum_pl += mid - v[i];
    }
    if (sum_min - (sum_min * k) / 100 > sum_pl)
      l = mid;
    else
      r = mid;
  }
  cout << setprecision(10) << fixed << mid;
}
