#include <bits/stdc++.h>
using namespace std;
vector<double> v(10005);
long long n;
double k;
bool fin(double x) {
  double s1 = 0.0, s2 = 0.0;
  for (long long(i) = 0; (i) < (long long)(n); ++(i)) {
    if (v[i] > x)
      s1 += v[i] - x;
    else
      s2 += (x - v[i]);
  }
  s1 -= (s1 * k / 100.0);
  if (s1 >= s2)
    return 1;
  else
    return 0;
}
int main() {
  cin >> n >> k;
  for (long long(i) = 0; (i) < (long long)(n); ++(i)) {
    cin >> v[i];
  }
  double l = 0.0, h = 1000.0;
  double mid;
  for (long long(i) = 0; (i) < (long long)(100); ++(i)) {
    mid = (l + h) / 2;
    if (fin(mid)) {
      l = mid;
    } else
      h = mid;
  }
  cout << fixed << setprecision(9) << mid;
  return 0;
}
