#include <stdio.h>
int main() {
    int n,a,b,c = 0;
    int k = 0;
    scanf("%d",&n);
    while(n--){
    	scanf("%d %d",&a,&b);
    	k = a/b;
    	if(k==2)
    	    c = 3 * b;
    	else
    	    c = 2 * b;
    	if(a%c==0)
    	    c = 3 * b;
    	printf("%d\n",c);
	}
}