#include <bits/stdc++.h>
using namespace std;
int abs(int, int);
bool b(double, double, double[], int);
int fin(int[], int, int);
int main() {
  int n;
  double p;
  cin >> n >> p;
  p = 1 - p / 100;
  double a[10000];
  for (int i = 0; i < n; i++) cin >> a[i];
  double l = 0;
  double c;
  double h = 1000;
  for (int i = 0; i < 1000; i++) {
    c = (l + h) / 2;
    if (b(c, p, a, n))
      l = c;
    else
      h = c;
  }
  printf("%.6f", (l + h) / 2);
  return 0;
}
bool b(double x, double p, double a[], int n) {
  double a1 = 0;
  double a2 = 0;
  for (int i = 0; i < n; i++) {
    if (a[i] >= x) {
      a1 += a[i] - x;
    } else
      a2 += x - a[i];
  }
  a1 = a1 * p;
  return (a1 >= a2);
}
