#include<stdio.h>
int gcd(int a,int b){              //递归
    if(a%b==0)
        return b;
    else
        return gcd(b,a%b);
}
int main(){
    int n,i,a,b,c;
    while(~scanf("%d",&n)){
        while(n--){
            scanf("%d%d",&a,&c);
            b=2*c;
            while(gcd(a,b)!=c)
                b+=c;
            printf("%d\n",b);
        }
    }
    return 0;
}