#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#pragma GCC optimize("unroll-loops")
using namespace std;
const int INF = int(1e9), mod = 10056, N = int(1e6) + 5;
double n, k;
double a[N];
bool check(double x) {
  double second = 0;
  double s2 = 0;
  for (int i = 0; i < n; i++) {
    if (a[i] > x) {
      second += a[i] - x;
    } else {
      s2 += x - a[i];
    }
  }
  second = second - second * k / 100.0;
  if (second > s2) {
    return 1;
  }
  return 0;
}
int main() {
  ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  cin >> n >> k;
  for (int i = 0; i < n; i++) {
    cin >> a[i];
  }
  double l = 0.0;
  double r = 1000.0;
  double ans = 0;
  while (r - l > 1e-7) {
    double mid = (l + r) / 2;
    if (check(mid)) {
      l = mid;
      ans = mid;
    } else {
      r = mid;
    }
  }
  cout << fixed << setprecision(10);
  cout << l << endl;
}
