#include <iostream>
#include <string>
#include <cctype>
#include <algorithm>

int main()
{
	std::string mystring
	{
		"AaABbB"
	};
	std::sort(std::begin(mystring), std::end(mystring), [](std::string::value_type const &a, std::string::value_type const &b)
	{
	    return std::tolower(a) < std::tolower(b);
	});
	std::cout << mystring << std::endl;
}