#include <bits/stdc++.h>
using namespace std;
long long int pow_mod(long long int a, long long int b) {
  long long int res = 1;
  while (b != 0) {
    if (b & 1) {
      res = (res * a) % 1000000007;
    }
    a = (a * a) % 1000000007;
    b /= 2;
  }
  return res;
}
void solve() {
  long long int n, k;
  cin >> n >> k;
  double a[n];
  for (long long int i = 0; i < n; i++) cin >> a[i];
  sort(a, a + n);
  double high, low, mid;
  high = 1000.0;
  low = 0.0;
  while (high - low > .00000000001) {
    double h = 0, l = 0;
    mid = (high + low) / 2.0;
    for (long long int i = 0; i < n; i++) {
      if (a[i] > mid)
        h += (a[i] - mid);
      else
        l += (mid - a[i]);
    }
    h = h * (1 - k / 100.0);
    if (h > l)
      low = mid;
    else
      high = mid;
  }
  cout << fixed << setprecision(9) << mid << endl;
}
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long long int t;
  t = 1;
  while (t--) solve();
  return 0;
}
