#include <bits/stdc++.h>
using namespace std;
int64_t a[10004], n, k;
bool check(double e) {
  double sp = 0, lp = 0;
  for (int64_t i = 0; i < n; i++) {
    if (a[i] > e)
      sp += a[i] - e;
    else
      lp += e - a[i];
  }
  return lp <= sp - (sp * k) / 100.0;
}
int32_t main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int64_t tt = 1, m, d, x = 1, y = 1, cnt = 0, q = 0, sum = 0, i, j;
  cin >> n >> k;
  for (i = 0; i < n; i++) {
    cin >> a[i];
  }
  double hi = 1000, lo = 0, mid = 500;
  for (j = 0; j < 110; j++) {
    mid = (hi + lo) / 2;
    if (check(mid))
      lo = mid;
    else
      hi = mid;
  }
  cout << setprecision(10) << fixed << mid;
}
