#include <bits/stdc++.h>
using namespace std;
double eps = 1e-7;
int main() {
  int n;
  while (cin >> n) {
    int k;
    cin >> k;
    vector<int> a(n);
    int sum = 0;
    for (int i = 0; i < n; i++) {
      cin >> a[i];
      sum += a[i];
    }
    double hi = sum / (double)n;
    double lo = 0;
    while (hi - lo > eps) {
      double mid = (hi + lo) / 2;
      double res = 0;
      for (int i = 0; i < n; i++) {
        if (mid < a[i]) {
          res += (a[i] - mid) * (100 - k) / 100;
        } else {
          res -= (mid - a[i]);
        }
      }
      if (res >= 0) {
        lo = mid;
      } else {
        hi = mid;
      }
    }
    printf("%.7f\n", lo);
  }
  return 0;
}
