#include<iostream>
using namespace std;

int main(){
	//part 1
	//not able to compile
    int *b1 = 0;
    const int *& n1 = b1;
    
    
    //part 2
    //able to compile
    int a2 = 0;
    int *b2 = &a2;
    const int & n2 = *b2;
    cout << n2 << endl; // n = 0
    *b2 = 3;
    cout << n2 << endl; // n = 3
    
    return 0;
}