#include <iostream>

int main( ) {
   int a = 5;
   int& b = a;
   b += 1;
   std::cout << a << " " << b << "\n";
   
   int x = 0;
   int& y = x;
   int& z = y;
   z += 1;
   std::cout << x << " " << y << " " << z << "\n";
}