#include <bits/stdc++.h>
using namespace std;
const int64_t nax = 1e4 + 100;
int64_t a[nax], n, k;
bool good(double val) {
  double energy = 0;
  for (int64_t i = 0; i < n; ++i) {
    if (a[i] >= val)
      energy += a[i] - val;
    else
      energy -= 100 * (val - a[i]) / double(100 - k);
  }
  return energy >= 0;
}
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout << fixed << setprecision(7);
  cin >> n >> k;
  for (int64_t i = 0; i < n; ++i) cin >> a[i];
  double l = 0, r = 1001, best = 0;
  for (int64_t i = 0; i < 30; ++i) {
    double mid = (l + r) / (double)2;
    if (good(mid)) {
      l = best = mid;
    } else {
      r = mid;
    }
  }
  cout << best;
}
