#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<int> a(n);
    queue<int> q;
    for(int i = 0; i < n; i++){
        cin >> a[i];
        q.push(i);
        v ^= a[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 = [&](){
        while(!q.empty()){
            int i = q.front();
            q.pop();
            if((a[i] ^ v) <= a[i]){
                cout << i + 1 << " " << a[i] - (v ^ a[i]) << endl;
                update(i, a[i] - (v ^ a[i]));
                if(a[i] != 0)q.push(i);
                return;
            }
            if(a[i] != 0)q.push(i);
        }
    };
    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);
    }
}