#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k;
  while (cin >> n >> k) {
    vector<int> a(n);
    vector<double> b(n);
    for (int i = (0); i < ((n)); ++i) cin >> a[i];
    if (n == 1 || count((a).begin(), (a).end(), a[0]) == n) {
      cout << a[0] << endl;
      continue;
    }
    sort((a).rbegin(), (a).rend());
    double l = *min_element((a).begin(), (a).end());
    double r = *max_element((a).begin(), (a).end());
    double res = 0;
    for (int i = (0); i < ((n)); ++i) b[i] = (double)a[i];
    for (int T = (0); T < ((100)); ++T) {
      double m = (l + r) / 2.;
      double pos = 0, neg = 0;
      for (int i = (0); i < ((n)); ++i) {
        if (m < b[i])
          pos += b[i] - m;
        else
          neg += m - b[i];
      }
      if (pos * (100. - k) / 100. < neg) {
        r = m;
      } else {
        l = m;
      }
      res = m;
    }
    cout << setprecision(10) << res << endl;
  }
  return 0;
}
