#include <bits/stdc++.h>
using namespace std;
ifstream fin("Sisend.txt");
int n;
double k, jad[10005], cc = 0.0000001;
vector<pair<long long, int>> pr;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cerr.tie(0);
  cin >> n >> k;
  for (int(i) = (0); ((i)) < ((n)); ((i))++) cin >> jad[i];
  double l = 0, r = 1000;
  while (abs(r - l) > cc) {
    double m = (l + r) / 2;
    double mi = 0, ma = 0;
    for (int(i) = (0); ((i)) < ((n)); ((i))++)
      if (jad[i] > m)
        ma += jad[i] - m;
      else
        mi += m - jad[i];
    if (ma - ma * k / 100 > mi)
      l = m;
    else
      r = m;
  }
  cout << setprecision(10) << fixed << l << endl;
}
