#include <bits/stdc++.h>
using namespace std;
double a[10006];
int n;
double k;
double is_true(double mid) {
  double in = 0;
  for (int i = 0; i < n; i++) {
    if (a[i] < mid)
      in += mid - a[i];
    else
      in -= (a[i] - mid) * (1 - k / 100);
  }
  return in;
}
int main() {
  int i;
  cin >> n >> k;
  for (i = 0; i < n; i++) cin >> a[i];
  double mid, left = 0.0, right = 1000.0;
  while (right - left > 1e-7) {
    mid = (left + right) / 2;
    if (is_true(mid) < 0)
      left = mid;
    else if (is_true(mid) > 0)
      right = mid;
    else
      break;
  }
  printf("%.6f\n", mid);
  return 0;
}
