#include <bits/stdc++.h>
using namespace std;
int n, k;
int a[10005];
bool check(double num) {
  double val = 0;
  for (int i = 0; i < n; i++) {
    if (a[i] - num > 0) {
      val += (a[i] - num) * (100 - k) / 100;
    }
  }
  for (int i = 0; i < n; i++) {
    if (a[i] < num) {
      val -= (num - a[i]);
    }
  }
  if (val < 0)
    return 0;
  else
    return 1;
}
int main() {
  cin >> n >> k;
  for (int i = 0; i < n; i++) {
    cin >> a[i];
  }
  double l = 0, r = 1000;
  while (r - l > 1e-7) {
    double mid = (l + r) / 2;
    if (check(mid)) {
      l = mid;
    } else {
      r = mid;
    }
  }
  printf("%.7f\n", l);
  return 0;
}
