#include <bits/stdc++.h>
using namespace std;
double a[10001];
double bins(int n, int k) {
  double l = 0;
  double r = 1e8 + 1;
  for (int j = 0; j < 70; j++) {
    double c = l + (r - l) / 2;
    double sum = 0;
    double s = 0;
    for (int i = 0; i < n; i++)
      if (a[i] > c)
        sum += (a[i] - c);
      else
        s += (c - a[i]);
    if (k * sum / 100.0 > s)
      l = c;
    else
      r = c;
  }
  return r;
}
int main() {
  int n, k;
  cin >> n >> k;
  for (int i = 0; i < n; i++) scanf("%lf", a + i);
  printf("%.10lf", bins(n, 100 - k));
}
