#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e4 + 100;
double a[maxn];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int n;
  double k;
  cin >> n >> k;
  for (int i = 0; i < n; i++) cin >> a[i];
  double lo = 0, hi = 1000;
  int cnt = 100;
  while (cnt--) {
    double mid = (lo + hi) / 2;
    double sum1 = 0, sum2 = 0;
    for (int i = 0; i < n; i++)
      if (a[i] >= mid)
        sum1 += a[i] - mid;
      else
        sum2 += mid - a[i];
    if (sum2 <= sum1 - (sum1 * k / 100))
      lo = mid;
    else
      hi = mid;
  }
  cout.precision(9);
  cout << fixed << lo << endl;
  return 0;
}
