#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  double k, left, right, mid, sum1, sum2;
  cin >> n >> k;
  double arr[n];
  for (int i = 0; i < n; i++) {
    cin >> arr[i];
  }
  sort(arr, arr + n);
  left = 0.0;
  right = arr[n - 1];
  while (left <= right) {
    double a = 0.0, b = 0.0, sum_a = 0.0, sum_b = 0.0;
    mid = (left + right) / 2.0;
    for (int i = 0; i < n; i++) {
      if (arr[i] > mid) {
        a++;
        sum_a += arr[i];
      } else {
        b++;
        sum_b += arr[i];
      }
    }
    sum1 = (sum_a - (a * mid)) * ((100 - k) / 100.0);
    sum2 = mid * b - sum_b;
    if (abs(sum1 - sum2) < 0.0000001) {
      cout << fixed << setprecision(9) << mid;
      break;
    }
    if (sum1 > sum2) {
      left = mid;
    }
    if (sum1 < sum2) {
      right = mid;
    }
  }
}
