import sys
from collections import defaultdict, deque, Counter
sys.setrecursionlimit(5 * 10 ** 5)
from pypyjit import set_param
set_param('max_unroll_recursion=-1')
input = lambda: sys.stdin.readline().rstrip()
ii = lambda: int(input())
mi = lambda: map(int, input().split())
li = lambda: list(mi())
inf = 2 ** 63 - 1
mod = 998244353


n = ii()

a = li()


class segtree():
    n=1
    size=1
    log=2
    d=[0]
    op=None
    e=10**15
    def __init__(self,V,OP,E):
        self.n=len(V)
        self.op=OP
        self.e=E
        self.log=(self.n-1).bit_length()
        self.size=1<<self.log
        self.d=[E for i in range(2*self.size)]
        for i in range(self.n):
            self.d[self.size+i]=V[i]
        for i in range(self.size-1,0,-1):
            self.update(i)
    def set(self,p,x):
        assert 0<=p and p<self.n
        p+=self.size
        self.d[p]=x
        for i in range(1,self.log+1):
            self.update(p>>i)
    def get(self,p):
        assert 0<=p and p<self.n
        return self.d[p+self.size]

    def __setitem__(self, p, x):
        self.set(p, x)
    
    def __getitem__(self, p):
        if isinstance(p, int):
            return self.get(p)
        else:
            return self.prod(p.start, p.stop)

    def prod(self,l,r):
        assert 0<=l and l<=r and r<=self.n
        sml=self.e
        smr=self.e
        l+=self.size
        r+=self.size
        while(l<r):
            if (l&1):
                sml=self.op(sml,self.d[l])
                l+=1
            if (r&1):
                smr=self.op(self.d[r-1],smr)
                r-=1
            l>>=1
            r>>=1
        return self.op(sml,smr)
    
    def all_prod(self):
        return self.d[1]

    def update(self,k):
        self.d[k]=self.op(self.d[2*k],self.d[2*k+1])

    def __str__(self):
        return str([self.get(i) for i in range(self.n)])


xor = 0
di = {}

for i in range(n):
    if a[i] not in di:
        di[a[i]] = set([i])
    di[a[i]].add(i)

for v in a:
    xor ^= v
a = segtree(a, max, -inf)

def oppo():
    global xor
    i, k = mi()
    i -= 1
    if a[i] not in di:
        raise Exception
    di[a[i]].discard(i)
    xor ^= a[i]
    a[i] -= k
    xor ^= a[i]
    if a[i] not in di:
        di[a[i]] = set([i])
    di[a[i]].add(i)
def me():
    global xor
    i = di[a.all_prod()].pop()
    k = xor
    xor = 0
    a[i] -= k
    print(i + 1, k, flush=True)
    if a[i] not in di:
        di[a[i]] = set([i])
    di[a[i]].add(i)

if xor == 0:
    print(0, flush=True)
    oppo()
else:
    print(1, flush=True)

while True:
    me()
    r = ii()
    if r == -1:
        exit()
    oppo()
    r = ii()
    if r == -1:
        exit()