#include <string>
#include <stdio.h>

struct List
{
 std::string buf_;
};


int concat(List &l1,List l2)
{
 l1.buf_ += l2.buf_;
 return l1.buf_.size();
}

main()
{
 List l1,l2;
 l1.buf_ = "萌";
 l2.buf_ = "ろろろろ";
 concat(l1, l2);
 printf("%s", l1.buf_.c_str());
}