#include <bits/stdc++.h>
using namespace std;
void Mohamed_Galal() {
  ios_base::sync_with_stdio(0);
  cin.tie(NULL), cout.tie(NULL);
}
const int N = 1e4 + 5;
int arr[N];
double n, k, percent;
bool valid(double Mid) {
  double res = 0;
  for (size_t i = 0; i < n; i++)
    arr[i] > Mid ? res += (arr[i] - Mid)* percent : res -= (Mid - arr[i]);
  return res > 0;
}
double BinarySearch(double First, double End) {
  double ans = 0;
  while (First <= End) {
    double Mid = (First + End) / 2;
    if (valid(Mid)) {
      ans = Mid;
      First = Mid + (1 / 1e7);
    } else
      End = Mid - (1 / 1e7);
  }
  return ans;
}
int main() {
  Mohamed_Galal();
  cin >> n >> k;
  percent = 1 - (k / 100);
  for (size_t i = 0; i < n; i++) cin >> arr[i];
  cout << fixed << setprecision(6) << BinarySearch(0, 1000) << endl;
  return 0;
}
