#include <bits/stdc++.h>
using namespace std;
const int inf = 1000 * 1000 * 1000;
int n;
double k, ar[100000];
int main() {
  scanf("%d%lf", &n, &k);
  k = 1 - k / 100;
  for (int i = 0; i < n; i++) scanf("%lf", &ar[i]);
  double L = 0, R = 1001, m;
  while (R - L > 1e-8) {
    m = (L + R) / 2;
    double p = 0, h = 0;
    for (int i = 0; i < n; i++) {
      if (ar[i] <= m) {
        h += m - ar[i];
      } else
        p += ar[i] - m;
    }
    if (p * k >= h)
      L = m;
    else
      R = m;
  }
  printf("%0.7lf", L);
  return 0;
}
