#include <bits/stdc++.h>
using namespace std;
const double eps = 0.0000000001;
int n, k;
int a[10000];
double bi(double l, double r) {
  if (r - l < eps) {
    return l;
  } else {
    double m = (l + r) / 2;
    double t1 = 0, t2 = 0;
    for (int i = 0; i < n; i++) {
      if (a[i] < m) {
        t1 += m - a[i];
      } else {
        t2 += a[i] - m;
      }
    }
    if (t1 == (t2 * (100 - k)) / 100) {
      return m;
    }
    if (t1 > (t2 * (100 - k)) / 100) {
      return bi(l, m);
    }
    if (t1 < (t2 * (100 - k)) / 100) {
      return bi(m, r);
    }
  }
}
int main() {
  cout.precision(20);
  cin >> n >> k;
  int q1, q2;
  q1 = 0;
  q2 = 0;
  for (int i = 0; i < n; i++) {
    cin >> a[i];
    if (a[i] < a[q1]) {
      q1 = i;
    }
    if (a[i] > a[q2]) {
      q2 = i;
    }
  }
  if (q1 == q2) {
    cout << a[q1];
  } else {
    cout << bi(a[q1], a[q2]);
  }
  return 0;
}
