#include <bits/stdc++.h>
using namespace std;
template <class T>
void check_max(T& a, T b) {
  if (a < b) a = b;
}
template <class T>
void check_min(T& a, T b) {
  if (a > b) a = b;
}
const int MAXN = 10100;
int n, k;
double per;
double a[MAXN];
int main() {
  cin >> n >> k;
  per = (double)k / 100;
  for (int _t = n, i = 0; i < _t; i++) cin >> a[i];
  sort(a, a + n);
  double l = 0, r = 1000;
  while (r - l > 1e-8) {
    double m = (r + l) / 2;
    double more = 0, less = 0;
    for (int _t = n, i = 0; i < _t; i++)
      if (a[i] > m)
        more += a[i] - m;
      else
        less += m - a[i];
    if (more * (1 - per) >= less)
      l = m;
    else
      r = m;
  }
  double ans = (l + r) / 2;
  printf("%.7lf\n", ans);
  return 0;
}
