#include <bits/stdc++.h>
using namespace std;
int n;
double k, a[10005];
bool ok(double x) {
  double s1 = 0, s2 = 0;
  for (int i = 0; i < n; i++)
    if (a[i] <= x)
      s1 += x - a[i];
    else
      s2 += a[i] - x;
  s2 *= k;
  if (s2 < s1) return true;
  return false;
}
int main() {
  scanf("%d %lf", &n, &k);
  k = 1 - k / 100.0;
  double l = 0, r = 0, mid;
  for (int i = 0; i < n; i++) {
    scanf("%lf", &a[i]);
    r = max(a[i], r);
  }
  while (r - l > 1e-10) {
    mid = (l + r) / 2.0;
    if (ok(mid))
      r = mid;
    else
      l = mid;
  }
  printf("%.10lf\n", (l + r) / 2.0);
  return 0;
}
