#include <bits/stdc++.h>
using namespace std;
void winter_is_coming() {
  std::ios_base::sync_with_stdio(0);
  cin.tie(NULL);
  cout.tie(NULL);
}
double k, arr[10001];
int n;
double check(double md, double k) {
  double sum = 0;
  for (int i = 0; i < n; i++)
    if (arr[i] > md) {
      double x = arr[i] - md;
      sum += (x - (x * k / 100));
    } else if (arr[i] < md) {
      double x = md - arr[i];
      sum -= x;
    }
  return sum;
}
int main() {
  winter_is_coming();
  int t = 100;
  double mx = 0;
  cin >> n >> k;
  for (int i = 0; i < n; i++) cin >> arr[i], mx = max(mx, arr[i]);
  double lo, hi, md, ans = 0;
  lo = 0, hi = 1000;
  while (t--) {
    md = (lo + hi) / 2;
    double z = check(md, k);
    if (z >= 0) {
      ans = md;
      lo = md;
    } else
      hi = md;
  }
  cout << fixed << setprecision(9) << ans << endl;
  return 0;
}
