text: #include <bits/stdc++.h>
  using namespace std;
  typedef long long ll ;
  const int N=100003;
  const double eps=1e-7;
  int n,k;
  int arr[N];
  bool ok(double ss){
     double mm=0;
      double posi=0;
  
  for(int i=0;i<n;i++){
      if(ss > arr[i]){
          mm+=(ss-arr[i]);
      }else{ //if(ss < arr[i]){
          posi+=((arr[i]-ss)-((arr[i]-ss)*(1.0*k/100)));
      }
      }
  return posi >= mm;
  }
  
  int main(){
      ios_base::sync_with_stdio(false);
      cin.tie(nullptr);
  
  cin>>n>>k;
  for(int i=0;i<n;i++) cin>>arr[i];
  
   double i = 0;
      double sz = 1000;
  
      for (sz /= 2; sz > eps; sz /= 2) {
          if (ok(i + sz))
              i += sz;
      }
  
  
  
  cout<<fixed<<setprecision(9)<<i<<endl;
  
      return 0;
  }