UVA-11388-GCD-LCM

//scanf is faster than gets...if we need gets then use it otherwise should not use.
#include<stdio.h>
int main()
{
int n,m,t;
scanf("%d",&t);
while(t--)
{
    scanf("%d%d",&m,&n);
    if(n%m==0)
        printf("%d %d\n",m,n);
    else
        puts("-1\n");
}
return 0;
}