#include <bits/stdc++.h>
using namespace std;
void A4E() {
  ios_base::sync_with_stdio(0);
  cin.tie(NULL);
}
int main() {
  int i, j, n, t;
  cin >> n;
  double f;
  cin >> f;
  int a[100001];
  for (int i = 0; i < n; i += 1) cin >> a[i];
  double l = 0, h = 1010, m, take;
  while (h - l > 1e-9) {
    m = (h + l) / 2.0;
    take = 0;
    for (int i = 0; i < n; i += 1) {
      if (a[i] > m)
        take += (a[i] - m) * (1 - f / 100.0);
      else
        take += a[i] - m;
    }
    if (take > 0.0)
      l = m;
    else
      h = m;
  }
  printf("%lf\n", m);
  return 0;
}
