#include<stdio.h>

int gcd(int a,int b){
	return b==0? a:gcd(b,a%b); 
}

int main(void){
	int n,a,b,c;
	while(scanf("%d",&n)!=EOF){  
        while(n--){  
            scanf("%d%d",&a,&b);  
            c=2*b;  
            while(gcd(a,c)!=b)  
				c+=b;  
            printf("%d\n",c);  
        }  
    }  
    return 0;  
}