#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;
const int N = 200005;
const long double EPS = 1e-9;
const long double PI = acos(-1.);
int n, k;
double a[N];
bool ok(double mid) {
  double counter = 0;
  for (int i = 1; i <= n; i++) {
    double x = mid - a[i];
    if (x < EPS) {
      counter += -x + x * k / 100;
    }
    if (x > EPS) {
      counter -= x;
    }
  }
  return counter > -EPS;
}
int main() {
  cin >> n >> k;
  for (int i = 1; i <= n; i++) {
    scanf("%lf", &a[i]);
  }
  double st = 0, en = 1000;
  while (abs(st - en) > EPS) {
    double mid = (st + en) / 2;
    ok(mid) ? st = mid : en = mid;
  }
  printf("%.6f\n", st);
  return 0;
  return 0;
}
