#include <bits/stdc++.h>
using namespace std;
const double eps = 1e-9;
const int maxn = 10000;
int n, m;
int a[maxn];
int main() {
  scanf("%d%d", &n, &m);
  for (int i = 0; i < n; ++i) scanf("%d", &a[i]);
  m = 100 - m;
  double lo = 0, hi = 1000;
  double sol = 0;
  while (hi - lo > eps) {
    double mid = (lo + hi) / 2;
    double over(0), need(0);
    for (int i = 0; i < n; ++i)
      over += max(0.0, a[i] - mid), need += max(0.0, mid - a[i]);
    if (over * (m / 100.0) >= need)
      lo = mid + eps, sol = mid;
    else
      hi = mid - eps;
  }
  printf("%.10lf\n", sol);
  return 0;
}
