#include <bits/stdc++.h>
using namespace std;
const double eps = 1e-9;
double a[20000], l, r, mid, x, y;
int n, k;
int main() {
  scanf("%d%d", &n, &k);
  l = r = 0.0;
  for (int i = 0; i < n; i++) scanf("%lf", a + i), r = max(r, a[i]);
  sort(a, a + n);
  while (r - l > eps) {
    x = y = 0.0;
    mid = ((r + l) * 1.0) / 2.0;
    for (int i = 0; i < n; i++)
      if (a[i] < mid)
        x += mid - a[i];
      else
        y += a[i] - mid;
    y = y - (y * k) / 100.0;
    if (y > x)
      l = mid;
    else
      r = mid;
  }
  printf("%.8lf", l);
  return 0;
}
