#include <iostream>

using namespace std;

int main()
{
  int integer;
  cout<<"Zadejte hexadecimalni cislo:"<<endl;
  cin >> hex >> integer;
  if (!cin.fail())
    {
    if (cin.peek() == ' ')
        {
        cout << "Nespravny vstup." << endl;
        return(0);
        }
    else
    {
      if (cin.peek() >= 'G' && cin.peek() <= 'Z')
        {
          cout << "Nespravny vstup.." << endl;
          return(0);
        }
      else if (cin.peek() >= 'g' && cin.peek() <= 'z')
        {
          cout << "Nespravny vstup." << endl;
          return(0);
        }
    cout << "Desitkove: " << integer << endl;
    }
    }
else
    {
      cout << "Nespravny vstup." << endl;
    }
  return 0;
}