#include <bits/stdc++.h>
using namespace std;
int n, k;
long long a[10005];
bool chec(long long x) {
  long long s = 0;
  int i;
  for (i = 0; i < n; i++) {
    if (a[i] > x)
      s = s + a[i] - x;
    else {
      s = s - ((x - a[i]) * 100) / k;
    }
  }
  return (s >= 0);
}
int main() {
  ios::sync_with_stdio(false);
  int i;
  cin >> n >> k;
  k = 100 - k;
  for (i = 0; i < n; i++) {
    cin >> a[i];
    a[i] *= 1000000000ll;
  }
  cout << fixed;
  cout << setprecision(8);
  long long m, l = 0, r = 1000 * 1000000000ll;
  if (chec(r)) l = r;
  while (r - l > 1) {
    m = (l + r) / 2;
    if (chec(m))
      l = m;
    else
      r = m;
  }
  cout << double(l) / 1000000000ll << endl;
  return 0;
}
