GCD Problem case 1 error?

#1

Here is my code.

Constraints
0 < N1 < 1000000000
0 < N2 < 1000000000

#include
using namespace std;

int main() {
int N1, N2;
cin >> N1;
cin >> N2;

if(N1==0)
	cout << N2;

if(N2==0)
	cout << N1;

if(N1==N2)
	cout << N1;

if(N1>N2)
	cout << (N1-N2, N2);
else
	cout << (N1, N2-N1);
return 0;

}