#include <bits/stdc++.h>
using namespace std;
const int INF = 100000000;
const double EPS = 1e-8;
int main() {
  int n, k;
  scanf("%d %d", &n, &k);
  vector<double> a(n);
  for (int i = 0; i < n; ++i) scanf("%lf", &a[i]);
  double sum = 0.0;
  for (int i = 0; i < n; ++i) sum += a[i];
  double l = 0.0, u = sum;
  for (int i = 0; i < 200; ++i) {
    double m = (l + u) * 0.5;
    double rest = 0.0, need = 0.0;
    for (int i = 0; i < n; ++i) {
      if (m > a[i])
        need += m - a[i];
      else
        rest += a[i] - m;
    }
    if (rest - rest * k * 0.01 < need)
      u = m;
    else
      l = m;
  }
  printf("%.20f\n", l);
}
