#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k, i;
  scanf("%d", &(n));
  scanf("%d", &(k));
  double A[n];
  for (i = 0; i < n; i++) scanf("%lf", &A[i]);
  double low = 0.0, high = 1000.0;
  double ans = 0.0;
  while (high - low > 1e-8) {
    double mid = (low + high) / 2;
    double excess = 0, less = 0;
    for (i = 0; i < n; i++) {
      if (A[i] > mid)
        excess += A[i] - mid;
      else
        less += mid - A[i];
    }
    excess -= excess * k / 100.0;
    if (excess >= less) {
      low = mid + 1e-8;
      ans = mid;
    } else
      high = mid - 1e-8;
  }
  printf("%.8f\n", ans);
}
