#include <bits/stdc++.h>
using namespace std;
void fast() {
  std::ios_base::sync_with_stdio(0);
  cin.tie(NULL);
  cout.tie(NULL);
}
void infile() { freopen("input.in", "r", stdin); }
void outfile() { freopen("output.in", "w", stdout); }
void fastt() { fast(); }
int n;
double arr[1000000], k;
bool valid(double x) {
  double sum1 = 0, sum2 = 0;
  for (int i = 0; i < n; i++) {
    if (arr[i] > x)
      sum1 += (arr[i] - x) - (arr[i] - x) * k;
    else if (arr[i] < x)
      sum2 += x - arr[i];
  }
  return sum1 - sum2 >= 0;
}
double fun() {
  double l = 0, r = arr[n - 1];
  double energy = 0;
  for (int i = 0; i < 100; i++) {
    double mid = (l + r) / 2;
    if (valid(mid)) {
      energy = mid;
      l = mid;
    } else
      r = mid;
  }
  return energy;
}
int main() {
  fastt();
  cin >> n >> k;
  k /= 100;
  for (int i = 0; i < n; i++) cin >> arr[i];
  sort(arr, arr + n);
  cout << fixed << setprecision(6) << fun() << "\n";
}
