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

int main(){
    //ios::sync_with_stdio(false);
    //cin.tie(0);
    int n, v = 0, p, x, s;
    cin >> n;
    vector<set<int>> tb(75001);
    vector<int> a(n);
    for(int i = 0; i < n; i++){
        cin >> a[i];
        tb[a[i]].insert(i);
        v ^= a[i];
    }
    auto update = [&](int p, int x){
        tb[a[p]].erase(p);
        v ^= a[p];
        a[p] -= x;
        v ^= a[p];
        tb[a[p]].insert(p);
    };
    auto my_turn = [&](){
        for(int j = v; j < 75000; j++){
            if((j ^ v) >= j)continue;
            if(tb[j].empty())continue;
            cout << (*tb[j].begin()) + 1 << " " << j - (j ^ v) << '\n';
            update(*tb[j].begin(), j - (j ^ v));
            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);
    }
}