#include <bits/stdc++.h>
using namespace std;
const long long N = 1e5 + 5;
long long n, k;
long long a[N];
bool check(long double x) {
  long double ans1 = 0, ans2 = 0;
  for (long long i = 0; i < n; i++) {
    if (a[i] > x) ans1 += (long double)(a[i] - x);
    if (x > a[i]) ans2 += (long double)(x - a[i]);
  }
  return ans1 * (100 - k) * 0.01 >= ans2;
}
int32_t main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cin >> n >> k;
  for (long long i = 0; i < n; i++) cin >> a[i];
  long double l = *min_element(a, a + n), r = *max_element(a, a + n) + 1;
  for (long long i = 0; i < 300; i++) {
    long double mid = (l + r) / 2;
    if (check(mid))
      l = mid;
    else
      r = mid;
  }
  cout << fixed << setprecision(12);
  cout << l << '\n';
}
