#include <cassert>
#include <set>
#include <array>
#include <vector>
#include <iostream>
using namespace std;

class State {
    int x = 0;
    array<set<pair<int, int>>, 17> elems;
    vector<int> iv;
public:
    State(int n) : iv(n) {};
    void add(int i, int v) {
        x ^= v;
        for (int b = 0; b < 17; ++b)
            if (v >> b & 1) elems[b].emplace(v, i);
        iv[i] = v;
    }
    int sum() const { return x; }
    void remove(int i, int k) {
        const int oval = iv[i];
        for (int b = 0; b < 17; ++b)
            if (oval >> b & 1) elems[b].erase(make_pair(oval, i));
        if (const int v = oval - k; v > 0)
            for (int b = 0; b < 17; ++b)
                if (v >> b & 1) elems[b].insert(make_pair(v, i));
        iv[i] -= k;
        x ^= oval ^ iv[i];
    }
    pair<int, int> next_move() {
        assert(x != 0);
        const int l = 31 - __builtin_clz(x);
        assert(x >> l & 1);
        assert((x >> (l + 1)) == 0);
        const auto [v, i] = *elems[l].begin();
        assert(v > (v ^ x));
        return make_pair(i, v - (v ^ x));
    }
};

int main() {
    int n; cin >> n;
    State s(n);
    
    for (int i = 0; i < n; ++i) {
        int a; cin >> a;
        s.add(i, a);
    }
    cout << int(s.sum() != 0) << endl;
    for (;;) {
        const int x = s.sum();
        cerr << "x = " << x << endl;
        if (x == 0) {
            int i, k; cin >> i >> k;
            i--;
            s.remove(i, k);
        } else {
            const auto [i, k] = s.next_move();
            s.remove(i, k);
            cout << i + 1 << ' ' << k << endl;
        
        }
        int r; cin >> r;
        if (r == -1) return 0;
    }
}