from heapq import heappop,heappush
from operator import itemgetter

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

XOR=0
for a in A:
    XOR^=a

if XOR==0:
    print(0,flush=True)

    i,k=map(int,input().split())
    XOR^=A[i-1]
    A[i-1]-=k
    XOR^=A[i-1]
    ret=int(input())
    if ret==-1:
        exit()
else:
    print(1,flush=True)

H=[]

for i in range(n):
    H.append((-A[i],i))
H.sort(key=itemgetter(0))

while H:
    k,ind=heappop(H)
    if A[ind]!=-k:
        continue

    k=-k
    nec=XOR^k
    print(ind+1,k-nec,flush=True)
    ret=int(input())
    if ret==-1:
        exit()
    A[ind]=nec
    XOR=0

    if nec!=0:
        heappush(H,(-nec,ind))

    i,k=map(int,input().split())
    XOR^=A[i-1]
    A[i-1]-=k
    XOR^=A[i-1]
    if A[i-1]!=0:
        heappush(H,(-A[i-1],i-1))
    ret=int(input())
    if ret==-1:
        exit()