import sys

sys.setrecursionlimit(200005)
int1 = lambda x: int(x)-1
pDB = lambda *x: print(*x, end="\n", file=sys.stderr)
p2D = lambda x: print(*x, sep="\n", end="\n\n", file=sys.stderr)
def II(): return int(sys.stdin.readline())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def LI1(): return list(map(int1, sys.stdin.readline().split()))
def LLI1(rows_number): return [LI1() for _ in range(rows_number)]
def SI(): return sys.stdin.readline().rstrip()
dij = [(0, 1), (-1, 0), (0, -1), (1, 0)]
# dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)]
inf = (1 << 63)-1
# inf = (1 << 31)-1
# md = 10**9+7
md = 998244353

from collections import Counter

def naive(l, r):
    n = l+r+1
    aa = [[0]*n for _ in range(n)]
    cnt = Counter()
    x = 0
    for j in range(l, r+1):
        for i in range(l, j+1):
            if i+j > l+r: break
            aa[i][j] = 1
            cnt[i+j] += 1
            x ^= i+j

    # print(l, r)
    print(x, sorted(cnt.items()))
    # p2D(aa)

def xum(a):
    if a%8 == 0: return a
    if a%8 == 1: return 1
    if a%8 == 4: return a+1
    if a%8 == 5: return 0
    if a%8 == 2: return a
    if a%8 == 3: return 1
    if a%8 == 6: return a+1
    if a%8 == 7: return 0

# x = 0
# for a in range(21):
#     if a%4 == 2 or a%4 == 3:
#         x ^= a
#         print(a, x)

def solve():
    l, r = LI()

    if l == r:
        print(l+r)
        return

    s = l*2
    t = l+r
    while t%4 == (s+2)%4 or t%4 == (s+3)%4: t -= 1
    # pDB(s, t)
    if s-3 > 0:
        ans = xum(t) ^ xum(s-3)
    else:
        ans = xum(t)

    print(ans)
    # naive(l, r)

for _ in range(II()):
    solve()