#include <bits/stdc++.h>
using namespace std;
inline void ss(int &n) {
  n = 0;
  char c = getchar();
  while (c < 48 || c > 57) c = getchar();
  while (c >= 48 && c <= 57) n = (n << 1) + (n << 3) + c - 48, c = getchar();
}
const int mod = 1000000007;
int a[10010], n, k;
bool get(double x) {
  double ret = 0;
  for (int i = 0; i < n; i++)
    if (a[i] > x) {
      double t = a[i] - x;
      ret += t - t * k / 100;
    } else
      ret -= x - a[i];
  return ret >= 1e-9;
}
int main() {
  scanf("%d", &n);
  scanf("%d", &k);
  for (int i = 0; i < n; i++) scanf("%d", &a[i]);
  double lo = 0, hi = 10000, mid = 0;
  int iter = 100;
  while (iter--) {
    mid = (lo + hi) / 2;
    bool t = get(mid);
    if (t)
      lo = mid;
    else
      hi = mid;
  }
  printf("%.6lf\n", mid);
  return 0;
}
