#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("Ofast")
int ah = 911382323;
int bh = 972663749;
template <typename F, typename S>
ostream &operator<<(ostream &os, const pair<F, S> &p) {
  return os << "(" << p.first << ", " << p.second << ")";
}
template <typename T>
ostream &operator<<(ostream &os, const vector<T> &v) {
  os << "{";
  typename vector<T>::const_iterator it;
  for (it = v.begin(); it != v.end(); it++) {
    if (it != v.begin()) os << ", ";
    os << *it;
  }
  return os << "}";
}
template <typename T>
ostream &operator<<(ostream &os, const set<T> &v) {
  os << "[";
  typename set<T>::const_iterator it;
  for (it = v.begin(); it != v.end(); it++) {
    if (it != v.begin()) os << ", ";
    os << *it;
  }
  return os << "]";
}
template <typename F, typename S>
ostream &operator<<(ostream &os, const map<F, S> &v) {
  os << "[";
  typename map<F, S>::const_iterator it;
  for (it = v.begin(); it != v.end(); it++) {
    if (it != v.begin()) os << ", ";
    os << it->first << " = " << it->second;
  }
  return os << "]";
}
long long dx[8] = {1, -1, 0, 0, 1, 1, -1, -1};
long long dy[8] = {0, 0, 1, -1, 1, -1, 1, -1};
bool fun(double mid, long long k, vector<long long> &v) {
  double more = 0, less = 0;
  for (long long i = 0; i < v.size(); i++) {
    more += max(v[i] - mid, 0.0);
    less += max(mid - v[i], 0.0);
  }
  return more * (100 - k) / 100 >= less;
}
int32_t main() {
  ios::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long long n, k;
  cin >> n >> k;
  vector<long long> v(n);
  for (long long i = 0; i < n; i++) cin >> v[i];
  cout << fixed << setprecision(7);
  double low = 0, high = *max_element(v.begin(), v.end());
  while (high - low > 1e-8) {
    double mid = low + (high - low) / 2;
    if (!fun(mid, k, v)) {
      high = mid;
    } else
      low = mid;
  }
  cout << (low) << "\n";
}
