#include <bits/stdc++.h>
using namespace std;
long long gcd(long long a, long long b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
long long lcm(long long a, long long b) { return (a / gcd(a, b)) * b; }
bool eq(double a, double b) { return !(fabs(a - b) > 0.000000001); }
int N, K, con[100009], total;
bool check(double car) {
  double cary[100009], over = 0;
  for (int i = 0; i < N; i++) {
    if (con[i] > car) {
      double x = (con[i] - car);
      over += (x - ((x * K) / 100.0));
    } else {
      over -= (car - con[i]);
    }
  }
  if ((over > 0.000000) || eq(over, 0.0000)) return true;
  return false;
}
int main() {
  cin >> N >> K;
  total = 0;
  for (int i = 0; i < N; i++) cin >> con[i], total += con[i];
  double hi = 10000, low = 0, res = 0.0000;
  int ks = 100;
  double mid;
  while (1) {
    if (hi - low < 0.000000001) break;
    mid = (hi + low) / 2.000000;
    bool ret = check(mid);
    if (ret) {
      res = max(res, mid);
      low = mid;
    } else {
      hi = mid;
    }
  }
  printf("%.8lf\n", res, mid);
  return 0;
}
