#include <bits/stdc++.h>
using namespace std;
double binary_search_max();
bool ok(double);
long long k, n;
double EN, EA;
int arr[100000];
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(NULL), cout.tie(NULL);
  cin >> n >> k;
  for (int i = 0; i < n; ++i) {
    cin >> arr[i];
  }
  cout << std::fixed;
  cout << std::setprecision(9);
  cout << binary_search_max();
  return 0;
}
double binary_search_max() {
  double low = 0, high = 1e4, mid = 0;
  int cnt = 1e3;
  while (low < high && cnt--) {
    mid = (low + high) / 2.0;
    if (ok(mid)) {
      low = mid;
    } else {
      high = mid;
    }
  }
  return mid;
}
bool ok(double ee) {
  EN = 0, EA = 0;
  for (int i = 0; i < n; ++i) {
    if (arr[i] < ee) {
      EN += ee - arr[i];
    } else if (arr[i] > ee) {
      double x = arr[i] - ee;
      EA += (x - (x * k / 100.0));
    }
  }
  if (EA >= EN) {
    return true;
  } else {
    return false;
  }
}
