#include <iostream>
using namespace std;

int& msub(int& a , int& b){
	int c = a - b ;
	return c ;
}

int main() {

    int a = 5, b=4, c=2; 
	int r = msub(a, msub(b,c));
	cout << "Should be 3: "<<r<<endl;

	// your code goes here
	return 0;
}