#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 100;
double a[N];
double k;
int n;
double l, r, m;
bool solve(double nva) {
  double bal = 0;
  for (int i = 0; i < n; ++i) {
    if (a[i] >= nva) {
      bal += k * (a[i] - nva);
    } else {
      bal += (a[i] - nva);
    }
  }
  return bal >= 0;
}
int main() {
  cin >> n >> k;
  k = (1 - k / 100.0);
  for (int i = 0; i < n; ++i) {
    cin >> a[i];
    r = max(r, a[i]);
  }
  l = 0;
  for (int i = 0; i < 200; ++i) {
    m = (l + r) / 2.;
    if (solve(m)) {
      l = m;
    } else {
      r = m;
    }
  }
  printf("%.6lf", r);
  return 0;
}
