#pragma GCC target("avx")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
using namespace std;
void solve() {
    int n;
    cin >> n;
    int xor_all = 0;
    vector<int> a(n);
    set<pair<int, int>> s;
    for( int i = 0; i < n; i++ ) {
        cin >> a[i];
        xor_all ^= a[i];
        s.insert(make_pair(a[i], i));
    }
    auto julys_turn = [&]() -> void {
        int i, k;
        cin >> i >> k;
        i--;
        xor_all ^= a[i]^(a[i]-k);
        s.erase(make_pair(a[i], i));
        s.insert(make_pair(a[i]-k, i));
        a[i] -= k;
    };
    auto my_turn = [&]() -> void {
        int i = (*s.rbegin()).second, k = a[i]-(xor_all^a[i]);
        s.erase(make_pair(a[i], i));
        s.insert(make_pair(xor_all^a[i], i));
        xor_all = 0;
        a[i] -= k;
        cout << i+1 << " " << k << endl;
    };
    auto ret = [&]() -> int {
        int ret_;
        cin >> ret_;
        return ret_;
    };
    if( xor_all == 0 ) {
        cout << 0 << endl;
        julys_turn();
        if( ret() == -1 ) return;
    }else {
        cout << 1 << endl;
    }
    while(true) {
        my_turn();
        if( ret() == -1 ) return;
        julys_turn();
        if( ret() == -1 ) return;
    }
}
int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int t;
    t = 1;
    // cin >> t;
    while(t--) solve();
}