#include <bits/stdc++.h>
using namespace std;
int main(int argc, char* argv[]) {
  int n, k;
  cin >> n >> k;
  vector<int> e;
  double l = -1, h = -1;
  for (int i = 0; i < n; i++) {
    int t;
    cin >> t;
    e.push_back(t);
    if ((l == -1) || (t < l)) l = t;
    if ((h == -1) || (t > h)) h = t;
  }
  while (h - l > 0.000000001) {
    double x = (h + l) / 2;
    int a = 0, b = 0;
    int up = 0, down = 0;
    for (vector<int>::iterator i = e.begin(); i != e.end(); i++) {
      if (*i > x) {
        a++;
        up += *i;
      } else {
        b++;
        down += *i;
      }
    }
    if ((up - a * x) * (100 - k) / 100 < x * b - down)
      h = x;
    else
      l = x;
  }
  cout.precision(9);
  cout << (h + l) / 2 << endl;
  return 0;
}
