#include <iostream>
#include <string>
static const std::string chars("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456\
789");


template<int n>
void pp(const std::string& p)
{
    for (std::string::const_iterator i = chars.begin();
         i != chars.end(); ++i)
      pp<n-1>(p + *i);
}
template<> void pp<1>(const std::string& p)
{
    for (std::string::const_iterator i = chars.begin();
         i != chars.end(); ++i)
      std::cout << p + *i << std::endl;
}
int main(int, char **)
{
    pp<3>("");
}