为什么WA?

#include<iostream>
using namespace std;
int main(){
    long a,b,r;cin>>a>>b;long oa=a,ob=b;
    while(a%b!=0){
        r=a%b;a=b;b=r;//辗转相除
    }cout<<r<<" "<<oa*ob/r;//gcd*lcm=a*b
}