#include <bits/stdc++.h>
using namespace std;
const int N = 2e6 + 4;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int n;
  cin >> n;
  double k;
  cin >> k;
  k = k / 100.0;
  double a[n + 5];
  for (int i = 0; i < n; i++) {
    cin >> a[i];
  }
  double l = 0.0, h = 1000.0, sum = 0.0, mid;
  for (int j = 0; j < 100; j++) {
    mid = (l + h) / 2.0;
    sum = 0.0;
    for (int i = 0; i < n; i++) {
      if (a[i] > mid) {
        sum += (1.0 - k) * (a[i] - mid);
      }
      if (a[i] < mid) {
        sum -= (mid - a[i]);
      }
    }
    if (sum >= 0.0) {
      l = mid;
    } else {
      h = mid;
    }
  }
  cout << fixed << setprecision(9) << l;
  return 0;
}
