#include <bits/stdc++.h>
using namespace std;
const double PI = atan(1) * 4;
int n, k, arr[10001];
double l = 0, r = 1e5, mid, res;
bool can(double mid) {
  double sum = 0;
  for (int i = 0; i < n; ++i) {
    if (arr[i] > mid) {
      sum += (arr[i] - mid) * k / 100.0;
    } else
      sum -= mid - arr[i];
  }
  if (sum >= 0)
    return true;
  else
    return false;
  if (sum >= n)
    return true;
  else
    return false;
}
int main(void) {
  cin >> n >> k;
  k = 100 - k;
  for (int i = 0; i < n; ++i) cin >> arr[i];
  for (int i = 0; i <= 100; ++i) {
    mid = (l + r) / 2;
    if (can(mid)) {
      res = mid;
      l = mid;
    } else
      r = mid;
  }
  printf("%.9lf", res);
}
