#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e4;
int n;
double k, ans;
int a[maxn];
double mid, r, l;
bool check(double mid) {
  double res = 0.0;
  for (int i = 0; i < n; i++) {
    double x = 0.0;
    if (a[i] > mid) {
      x = a[i] - mid;
      res += x * ((double)(100 - k) / 100.0);
    } else {
      res -= mid - a[i];
    }
  }
  if (res >= 0) {
    return true;
  } else {
    return false;
  }
}
int main() {
  cin >> n >> k;
  for (int i = 0; i < n; i++) {
    cin >> a[i];
  }
  l = 0;
  r = 1000;
  while (r - l > 1e-9) {
    mid = (l + r) / 2;
    if (check(mid)) {
      ans = mid;
      l = mid;
    } else {
      r = mid;
    }
  }
  cout << fixed << setprecision(9) << ans;
  return 0;
}
