#include <bits/stdc++.h>
using namespace std;

template <int LOG = 30> struct BinaryTrie {
    struct Node {
        long long cnt = 0;
        int ch[2] = {-1, -1};
    };
    std::vector<Node> ns;
    BinaryTrie() : ns(1) {}
    long long size() const { return ns[0].cnt; }
    long long operator[](int k) const { return find_kth(k, 0); }
    long long find_kth(long long k, long long xor_add = 0) const {
        assert(0 <= k && k < size());
        long long idx = 0, val = 0;
        for(int i=LOG-1; i>=0; i--) {
            long long c = xor_add >> i & 1;
            long long low_ch = ns[idx].ch[c];
            long long low_cnt = (low_ch >= 0 ? ns[low_ch].cnt : 0);
            if (k < low_cnt) {
                idx = low_ch;
            } else {
                k -= low_cnt;
                idx = ns[idx].ch[c ^ 1];
                val ^= 1LL << i;
            }
            assert(idx >= 0);
        }
        return val;
    }
    void add(long long val, long long cnt = 1) {
        assert(0 <= val && val < (1LL << LOG));
        int idx = 0;
        for(int i=LOG-1; i>=0; i--) {
            ns[idx].cnt += cnt;
            assert(ns[idx].cnt >= 0);
            int &nxt = ns[idx].ch[val >> i & 1];
            if (nxt == -1) {
                idx = nxt = ns.size();
                ns.emplace_back();
            } else {
                idx = nxt;
            }
        }
        ns[idx].cnt += cnt;
        assert(ns[idx].cnt >= 0);
    }
    long long lower_bound(long long val, long long xor_add = 0) {
        assert(0 <= val);
        if (val >= (1LL << LOG)) return size();
        int idx = 0;
        long long cnt = 0;
        for(int i=LOG-1; i>=0; i--) {
            int b = val >> i & 1, c = xor_add >> i & 1;
            int ch = ns[idx].ch[c];
            cnt += (b & (ch >= 0) ? ns[ch].cnt : 0);
            idx = ns[idx].ch[b ^ c];
            if (idx < 0 or ns[idx].cnt == 0) break;
        }
        return cnt;
    }
    long long count(long long val) const {
        assert(0 <= val && val < (1LL << LOG));
        int idx = 0;
        for(int i=LOG-1; i>=0; i--) {
            idx = ns[idx].ch[val >> i & 1];
            if (idx < 0 or ns[idx].cnt == 0) return 0;
        }
        return ns[idx].cnt;
    }
    long long count(long long L, long long R, long long xor_add = 0) {
        assert(0 <= L && L <= R && R <= (1LL << LOG));
        return lower_bound(R, xor_add) - lower_bound(L, xor_add);
    }
    long long xor_min(long long xor_add = 0) { return find_kth(0, xor_add); }
    long long xor_max(long long xor_add = 0) { return find_kth(size() - 1, xor_add); }
};

int main(){
    //ios::sync_with_stdio(false);
    //cin.tie(0);
    int n, v = 0, p, x, s;
    cin >> n;
    vector<int> a(n);
    BinaryTrie<20> BT;
    set<pair<int,int>> S;
    for(int i = 0; i < n; i++){
        cin >> a[i];
        v ^= a[i];
        BT.add(a[i], 1);
        S.insert({a[i], i});
    }
    auto update = [&](int p, int x){
        S.erase(make_pair(a[p], p));
        BT.add(a[p], -1);
        v ^= a[p];
        a[p] -= x;
        v ^= a[p];
        if(a[p] >= 1){
            S.insert(make_pair(a[p], p));
            BT.add(a[p], 1);
        }
    };
    auto my_turn = [&](){
        for(int i = 0; i < n; i++){
            if(a[i] == 0)continue;
            if((a[i] ^ v) < a[i]){
                cout << i + 1 << " " << a[i] - (v ^ a[i]) << endl;
                update(i, a[i] - (v ^ a[i]));
                return;
            }
        }
    };
    if(v == 0){
        cout << 0 << endl;
        cin >> p >> x;
        update(--p, x);
    }else{
        cout << 1 << endl;
        my_turn();
    }
    while(true){
        cin >> s;
        if(s == -1)break;
        my_turn();
        cin >> s;
        if(s == -1)break;
        cin >> p >> x;
        update(--p, x);
    }
}