#include <bits/stdc++.h>
using namespace std;
int N, i;
double K, A[10010], st, dr, mij;
bool check(double X) {
  double plus = .0;
  double minus = .0;
  for (int i = 1; i <= N; i++)
    if (A[i] >= X)
      plus = plus + A[i] - X;
    else
      minus = minus + X - A[i];
  plus = ((100.0 - K) / 100) * plus;
  if (plus >= minus)
    return true;
  else
    return false;
}
int main() {
  cin >> N >> K;
  for (i = 1; i <= N; i++) cin >> A[i];
  st = .0;
  dr = 1000.0;
  while (dr - st > 0.0000001) {
    mij = (st + dr) / 2;
    if (check(mij))
      st = mij;
    else
      dr = mij;
  }
  cout << fixed;
  cout << setprecision(6);
  cout << st << "\n";
  return 0;
}
