#include <bits/stdc++.h>
using namespace std;
const double EPS = 1e-7;
int n, k;
int a[10000];
double bsearch(double l, double r) {
  while (fabs(r - l) >= EPS) {
    double m = (r + l) / 2;
    double more = 0, less = 0;
    for (int i = 0; i < n; ++i)
      if (a[i] > m)
        more += a[i] - m;
      else if (a[i] < m)
        less += m - a[i];
    double sub = 100.0 * less / (100.0 - k);
    if (more > sub)
      l = m;
    else if (more < sub)
      r = m;
    else
      return m;
  }
  return (l + r) / 2;
}
int main() {
  cin >> n >> k;
  for (int i = 0; i < n; ++i) cin >> a[i];
  printf("%.6lf\n", bsearch(0, 2000));
}
