#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int n, b, i, j;
  double m;
  cin >> n >> m;
  double ar[n];
  m = 1.0 - m / 100.0;
  for (i = 0; i < n; i++) cin >> ar[i];
  double low = 0.0, high = 2000.0, mid;
  while (high - low > 1e-8) {
    double sm = 0.0;
    mid = low + (high - low) / 2.0;
    for (i = 0; i < n; i++) {
      if (mid > ar[i])
        sm -= mid - ar[i];
      else
        sm += m * (ar[i] - mid);
    }
    if (sm >= 0.0)
      low = mid;
    else
      high = mid;
  }
  printf("%.8lf\n", low);
  return 0;
}
