#include <bits/stdc++.h>
using namespace std;
const int inf = 1000 * 100 * 1000;
const double eps = 1.0e-10;
const int maxn = 10009;
double A[maxn];
int main() {
  int n;
  double k;
  scanf("%d%lf", &n, &k);
  for (int i = 0; i < n; i++) scanf("%lf", &A[i]);
  double l = 0;
  double r = 2000;
  while (r - l > eps) {
    double m = (l + r) / 2;
    double os = 0;
    double sum = 0;
    for (int i = 0; i < n; i++) {
      if (A[i] > m) {
        sum += A[i] - m;
        os += m;
      } else
        os += A[i];
    }
    if ((os + sum - sum * k / 100) < (m * n))
      r = m;
    else
      l = m;
  }
  printf("%.9f", l);
  return 0;
}
