import sys
input = sys.stdin.readline

T=int(input())

for tests in range(T):
    L,R=map(int,input().split())

    if (R-L)%4!=0:
        print((R-L)%2)
    elif (R-L)%8==0:
        print(R+L)
    else:
        print((R+L)^1)