#include <bits/stdc++.h>
using namespace std;
long double v[100000], k;
int n;
bool sepuede(long double x) {
  long double acum = 0;
  for (int i = 0; i < n; ++i) {
    if (v[i] > x) {
      acum += (v[i] - x);
      acum -= ((v[i] - x) * k / 100.0);
    } else {
      acum -= (x - v[i]);
    }
  }
  return acum >= 0;
}
int main() {
  cin >> n >> k;
  for (int i = 0; i < n; ++i) {
    cin >> v[i];
  }
  long double lo = 0, hi = 1000000, mid;
  while (abs(lo - hi) > 1e-7) {
    mid = (lo + hi) / 2;
    if (sepuede(mid)) {
      lo = mid;
    } else {
      hi = mid;
    }
  }
  cout << fixed << setprecision(8);
  cout << hi << '\n';
}
