#include <bits/stdc++.h>
using namespace std;
int a[10010];
double x, y;
int main() {
  int i, j, n, k, sum;
  double l, r, mid;
  scanf("%d%d", &n, &k);
  k = 100 - k;
  for (i = 0; i < n; i++) scanf("%d", &a[i]);
  l = 0, r = 1000;
  while (l < r - 1.0e-10) {
    mid = (l + r) / 2;
    x = y = 0;
    for (i = 0; i < n; i++)
      if (a[i] > mid)
        x += a[i] - mid;
      else
        y += mid - a[i];
    if (x * k / 100.0 > y)
      l = mid;
    else
      r = mid;
  }
  printf("%.9lf\n", mid);
  return 0;
}
