N = int(input())
A = list(map(int, input().split()))

nim = 0
for a in A:
    nim ^= a
t = 1 if nim else 0
print(t, flush=True)


def my_turn(nim):
    # print('myturn')
    # print(nim)
    # print(A)
    # B = sorted([(a, i) for i, a in enumerate(A)], reverse=True)
    for i, a in enumerate(A):
        na = a ^ nim
        if na < a:
            A[i] -= a - na
            print(i + 1, a - na, flush=True)
            break

    ret = int(input())
    if ret == 0:
        enemy_turn()
    else:
        exit()


def enemy_turn():
    # print("enemyturn")
    # print(A)
    idx, k = map(int, input().split())
    idx -= 1
    nim = A[idx]
    A[idx] -= k
    nim ^= A[idx]

    ret = int(input())
    if ret == 0:
        my_turn(nim)
    else:
        exit()


if t:
    my_turn(nim)
else:
    enemy_turn()