#include<stdio.h>
int gcd(int a,int b )
{
	int t=a%b;
	while(t){
		a=b;
		b=t;
		t=a%b;
	}
	return b;
}
int main()
{
	int n,a,b,c,i;
	scanf("%d",&n);
	while( n -- ){
		scanf("%d %d",&a,&b);
		for(i=2*b; ;i+=b)
		if(b==gcd(a, i))
		break;
		printf("%d\n",i);
	}
}