#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k;
  cin >> n >> k;
  vector<double> a(n);
  for (int i = 0; i < n; ++i) cin >> a[i];
  double sum = accumulate((a).begin(), (a).end(), 0);
  double low = 0, high = sum / n, p = 1.0 * k / 100;
  while (high - low > 1e-8) {
    double x = (low + high) / 2;
    double y = sum - x * n;
    double z = 0;
    for (int i = 0; i < n; ++i)
      if (a[i] > x) z += (a[i] - x) * p;
    if (y > z)
      low = x;
    else
      high = x;
  }
  printf("%.9f\n", low);
}
