#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  double k;
  cin >> n >> k;
  vector<double> v(n);
  for (int i = 0; i < n; ++i) cin >> v[i];
  sort(v.begin(), v.end());
  double a = v[0], b = v.back(), mid = (a + b) / 2;
  while (fabs(b - a) >= 1e-8) {
    mid = (a + b) / 2;
    double sa = 0, sb = 0;
    for (int i = 0; i < v.size(); ++i)
      if (v[i] > mid)
        sa += v[i] - mid;
      else
        sb += ((mid - v[i]) / (1 - k / 100.0));
    if (sa > sb)
      a = mid;
    else
      b = mid;
  }
  printf("%.7f\n", mid);
}
