#include<cstdio>
int T,a,b;
int plus(register int a,register int b) {
if(!a || !b) return a|b;
return plus((a & b) << 1,a ^ b);
}
int main() {
scanf("%d",&T);
for(register int i = 1;i <= T;++i) {
scanf("%d%d",&a,&b);
printf("%d\n",plus(a,b));
}
return 0;
}