from heapq import *

n = int(input())
aa = list(map(int, input().split()))

hp = []
x = 0
for i, a in enumerate(aa):
    x ^= a
    heappush(hp, (-a, i))

t = 1 if x else 0
print(t, flush=True)

ret = 0
while ret == 0:
    if t:
        i = a = -1
        while aa[i] != a:
            a, i = heappop(hp)
            a = -a
        b = x ^ a
        k = a-b
        print(i+1, k, flush=True)
    else:
        i, k = map(int, input().split())
        i -= 1
        a = aa[i]
        b = a-k
    x ^= a ^ b
    aa[i] = b
    if b: heappush(hp, (-b, i))
    ret = int(input())
    t ^= 1