#include <bits/stdc++.h>
using namespace std;
const long long BIG = 1000000007;
const double PI = 3.141592653589793238;
int main() {
  int n, k;
  cin >> n >> k;
  vector<int> v(n);
  for (int i = 0; i < n; i++) {
    cin >> v[i];
  }
  double start = 0, last = 1000, mid;
  for (int i = 0; i < 100; i++) {
    mid = start + (last - start) / 2;
    double lo = 0, hi = 0;
    for (int i = 0; i < n; i++) {
      if (v[i] >= mid) {
        hi += v[i] - mid;
      } else {
        lo += mid - v[i];
      }
    }
    if (hi - (hi * k) / 100 < lo) {
      last = mid;
    } else {
      start = mid;
    }
  }
  cout << fixed << setprecision(9) << mid;
}
