#include <bits/stdc++.h>
using namespace std;
int n, k;
long double a[20000];
int ifok(long double mid) {
  long double freea = 0;
  for (int i = 0; i < n; i++) {
    if (a[i] > mid) {
      freea += (a[i] - mid) * (1.0 - (long double)k / 100.0);
    } else {
      freea -= mid - a[i];
    }
  }
  return freea >= 0;
}
int main() {
  cin >> n >> k;
  long double maxa = 0;
  for (int i = 0; i < n; i++) {
    cin >> a[i];
    maxa = max(maxa, a[i]);
  }
  long double l = 0;
  long double r = maxa + 1;
  long double mid;
  while (1) {
    if (r - l < 1e-7) {
      break;
    }
    mid = (l + r) / 2;
    if (ifok(mid)) {
      l = mid;
    } else {
      r = mid;
    }
  }
  cout << setprecision(30) << l << endl;
  return 0;
}
