#include <bits/stdc++.h>
using namespace std;
int N, K, arr[10000];
const double EPS = 1e-9;
bool get(double x) {
  double store = 0;
  for (int i = 0; i < N; i++) {
    if (arr[i] > x) store += arr[i] - x;
  }
  for (int i = 0; i < N; i++) {
    if (arr[i] >= x) continue;
    double req = x - arr[i];
    double d = (100. * req) / (100 - K);
    store -= d;
  }
  return store + EPS >= 0;
}
int main() {
  cin >> N >> K;
  for (int i = 0; i < N; i++) cin >> arr[i];
  double low = 0, high = 1000, best = 0;
  for (int t = 0; t < 500; t++) {
    double mid = (low + high) / 2;
    if (get(mid)) {
      best = low = mid;
    } else {
      high = mid;
    }
  }
  printf("%.9lf\n", best);
  return 0;
}
