#include<stdio.h>
int gcd(int m,int n){
	int gcd,r;
	while(1){
		r=m%n;
		if(r==0)break;
		m=n;
		n=r;
	}
	gcd=n;
	return gcd;
}
int main(void){
	int n,a,b,c;
	scanf("%d",&n);
	while(n--){
		scanf("%d%d",&a,&b);
		c=b*2;
		while(gcd(a,c)!=b)c+=b;
		printf("%d\n",c);
	}
	return 0;
}