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

int n;

int inter(int i, int j){
    if (i == j) return 0;
    assert(i < j);
    cout << i+1 << " " << j+1 << endl;
    int v; cin >> v;
    if (v == -1) exit(0);
    return v;
}

void recurse(int begin, int end){
    if (begin+1 == end) return;

    int mid = (begin + end)>>1;
    recurse(begin, mid);
    recurse(mid, end);
    if (inter(mid-1, mid) == 0) return;

    deque<int> x, y;
    for (int i=begin; i<mid-1; i++) x.push_back(i);
    x.push_back(mid);

    y.push_back(mid-1);
    for (int i=mid+1; i<end; i++) y.push_back(i);

    for (int i=begin; i<end; i++){
        if (x[0] > y[0]) swap(x, y);
        int posl = x[0], posr = y[0];
        int v = inter(posl, posr);
        inter(i, posl);
        if (v == 0){
            x.pop_front();
        }
        else{
            swap(x[0], y[0]);
            y.pop_front();
        }
    }
}

signed main(){
    cin.tie(0)->sync_with_stdio(0);
    cin >> n;
    recurse(0, n);

    cout << "-1 -1" << endl;
}