#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 5;
int n, k, x[N];
bool ok(double m) {
  double need = 0, have = 0;
  for (int i = 0; i < n; i++) {
    if (x[i] > m) {
      have += (x[i] - m) - (((x[i] - m) * k) / 100.0);
    } else {
      need += m - x[i];
    }
  }
  if (need <= have) {
    return true;
  } else {
    return false;
  }
}
double bin() {
  double s = 0, e = 1e9, m, r = 0;
  for (int i = 0; i < 400; i++) {
    m = (s + e) / 2;
    if (ok(m)) {
      r = m;
      s = m;
    } else {
      e = m;
    }
  }
  return r;
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n >> k;
  for (int i = 0; i < n; i++) {
    cin >> x[i];
  }
  cout << fixed << setprecision(9) << bin();
  return 0;
}
