#include <bits/stdc++.h>
using namespace std;
const int N = 25;
int main() {
  int n, k;
  cin >> n >> k;
  double a[n];
  for (int i = (0), _b = (n); i < (_b); ++i) cin >> a[i];
  int t = 100;
  double lo = 0;
  double hi = 1000;
  double mi = 0;
  while (t-- > 0) {
    mi = (lo + hi) / 2;
    double extra = 0, need = 0;
    for (int i = (0), _b = (n); i < (_b); ++i) {
      if (a[i] > mi)
        extra += a[i] - mi;
      else if (a[i] < mi)
        need += mi - a[i];
    }
    if (extra * (100 - k) > 100 * need)
      lo = mi;
    else
      hi = mi;
  }
  cout << fixed << setprecision(15);
  cout << mi << endl;
  return 0;
}
