#include <bits/stdc++.h>
using namespace std;
inline void read(register int *n) {
  register char c;
  *n = 0;
  do {
    c = getchar();
  } while (c < '0' || c > '9');
  do {
    *n = c - '0' + *n * 10;
    c = getchar();
  } while (c >= '0' && c <= '9');
}
int main() {
  int n, k;
  cin >> n >> k;
  vector<int> a(n);
  for (register int i = (0); i < (int)(n); ++i) cin >> a[i];
  double mn = 0, mx = 1000;
  for (register int rep = (0); rep < (int)(60000000 / n); ++rep) {
    double mid = (mn + mx) / 2;
    double sum = 0, rem = 0;
    for (register int i = (0); i < (int)(n); ++i)
      if (mid < a[i])
        sum += a[i] - mid;
      else
        rem += mid - a[i];
    if (sum * (100 - k) / 100 > rem)
      mn = mid;
    else
      mx = mid;
  }
  cout << fixed << setprecision(8) << (mn + mx) / 2 << "\n";
  return 0;
}
