#include <bits/stdc++.h>
using namespace std;
double epsilon = 1e-7;
long long n, k;
long long arr[10003];
double ans;
bool check(double x) {
  double pos = 0, neg = 0;
  for (long long i = 0; i < n; i++) {
    if ((double)(arr[i]) - x > 0) {
      pos += (double)(arr[i]) - x;
    } else {
      neg += (x - (double)(arr[i]));
    }
  }
  ans = (double)((100 - k) * pos) / 100 - (double)neg;
  if (ans < 0) {
    return true;
  }
  return false;
}
int32_t main() {
  cin >> n >> k;
  for (long long i = 0; i <= n - 1; i++) {
    cin >> arr[i];
  }
  double l = 0;
  double r = 1000;
  long long i = 0;
  while (true) {
    double mid = l + (r - l) / 2;
    if (check(mid)) {
      r = mid;
    } else {
      l = mid;
    }
    if (abs(ans) < epsilon) {
      cout << fixed << setprecision(6) << l;
      return 0;
    }
  }
  return 0;
}
