c++分数减法

#include<bits/stdc++.h>
using namespace std;
int main(){
   	int a,b,c,d,fm,fz;
   	cin>>a>>b>>c>>d;
   	fm=b*d;
   	fz=a*d-b*c;
   	int gys=__gcd(fz,fm);
   	cout<<fz/gys<<" "<<fm/gys;
    return 0;
}