#include <bits/stdc++.h>
using namespace std;
int a[11000], n, k;
double g(double x) { return x - x * k / 100; }
int f(double x) {
  double aa = 0, b = 0;
  for (int i = 0; i < (n); ++i)
    if (a[i] <= x)
      aa += x - a[i];
    else
      b += g(a[i] - x);
  return aa < b;
}
int main() {
  scanf("%d", &n);
  scanf("%d", &k);
  for (int i = 0; i < (n); ++i) scanf("%d", &a[i]);
  double lo = 0, hi = *max_element(a, a + n), mid;
  for (int ii = 0; ii < (200); ++ii) {
    mid = (lo + hi) / 2;
    if (f(mid))
      lo = mid;
    else
      hi = mid;
  }
  printf("%.9lf\n", lo);
  return 0;
}
