#include <bits/stdc++.h>
using namespace std;
int a[10005];
int main() {
  int n, k;
  cin >> n >> k;
  for (int i = 0; i < n; i++) cin >> a[i];
  double lo = 0, hi = 1001;
  double r = 1 - k / 100.0;
  while (hi - lo > (1e-9)) {
    double x = (lo + hi) / 2;
    double falta = 0, sobra = 0;
    for (int i = 0; i < n; i++) {
      if (a[i] > x)
        sobra += a[i] - x;
      else
        falta += x - a[i];
    }
    if (sobra * r > falta)
      lo = x;
    else
      hi = x;
  }
  printf("%.8f\n", lo);
}
