#include <iostream>
using namespace std;

int main()
{
   string str;
   
   str = "Hello world";
   
   cout << str << endl;
   
   str = str + "another string";
   
   cout << str << endl;
   
   cout << "Enter another string: ";
   
   cin >> str;
   
   cout << str << endl;
   
   return 0;
}