#include <bits/stdc++.h>
using namespace std;
using LL = long long;
constexpr int N = 1e5 + 5;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  int n, k;
  cin >> n >> k;
  vector<int> in(n);
  for (int i = 0; i < n; i++) cin >> in[i];
  double l = 0, r = 1000, ans;
  for (int i = 0; i < 100; i++) {
    double m = (l + r) / 2;
    double need = 0, extra = 0;
    for (int j = 0; j < n; j++) {
      if (in[j] < m)
        need += m - in[j];
      else {
        double x = in[j] - m;
        extra += x - x * k / 100;
      }
    }
    if (extra >= need) {
      ans = m;
      l = m;
    } else {
      r = m;
    }
  }
  cout << setprecision(10) << ans << endl;
}
