#include <bits/stdc++.h>
using namespace std;
double arr[100005];
int main() {
  double n;
  cin >> n;
  double k;
  cin >> k;
  double maxi = -1;
  for (int i = 0; i < n; i++) {
    cin >> arr[i];
    maxi = max(maxi, arr[i]);
  }
  double low = 0, high = maxi;
  double excess = 0.0, slack = 0.0, mid;
  while (high - low >= 1e-8) {
    mid = (low + high) / 2.0;
    for (int i = 0; i < n; i++) {
      if (arr[i] > mid)
        excess += (arr[i] - mid);
      else
        slack += (mid - arr[i]);
    }
    double temp = excess - (excess * k) / 100.0;
    if (temp < slack) {
      high = mid;
    } else {
      low = mid;
    }
    excess = slack = 0.0;
  }
  printf("%0.9lf\n", low);
  return 0;
}
