#include <bits/stdc++.h>
using namespace std;
int n, k;
double p[10001];
int main() {
  cin >> n >> k;
  int i;
  double low, high, ans, sum;
  low = 1001, high = -1, sum = 0;
  for (i = 0; i < n; i++) {
    cin >> p[i];
    sum += p[i];
    if (low > p[i]) low = p[i];
    if (high < p[i]) high = p[i];
  }
  bool flag = false;
  if (low == high) flag = true;
  low = 0;
  high = sum;
  while (low < high) {
    double mid = (low + high) / 2.0, a = sum / n - mid / n * k / 100, sd = 0;
    for (i = 0; i < n; i++) {
      if (p[i] > a) sd += (p[i] - a);
    }
    if (sd == mid) {
      ans = a;
      break;
    } else if (sd > mid)
      low = mid;
    else
      high = mid;
  }
  if (flag) ans = p[0];
  cout << setiosflags(ios::fixed) << setprecision(9) << ans << endl;
}
