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

void solve(int t){
    int n;
    cin>>n;
    
    auto query = [&](int i,int j)->int{
        cout<<i<<" "<<j<<endl;
        int ans;
        cin>>ans;
        if(ans==-1)exit(0);
        return ans;
    };
    
    auto solve = [&](auto &solve,int l,int r){
        if(l==r)return;
        if(l+1==r)return;
        if(l+2==r){
            query(l,l+1);
            return;
        }
        
        int pivot = l+(rand()%(r-l));
        
        //cout<<"pivot = "<<pivot<<"\n";
        
        for(int i=l;i<pivot;i++){
            if(query(i,pivot)==1){
                pivot=i;
            }
        }
        
        //cout<<"fine parte 1\n";
        
        int last = r-1;
        while(last!=pivot){
            int passo;
            if(last>pivot){
                passo=-1;
            }else{
                passo=1;
            }
            
            //cout<<"step\n";
            
            bool ok = false;
            for(int i=last;i!=pivot;i+=passo){
                if(query(i,pivot)==1){
                    last=pivot;
                    pivot=i;
                    ok=true;
                    break;
                }
            }
            if(!ok)last=pivot;
            if(last!=pivot)last-=passo;
            
            //cout<<pivot<<" e "<<last<<"\n";
        }
        
        //cout<<"finito, ora pivot = "<<pivot<<"\n";
        
        solve(solve,l,pivot);
        solve(solve,pivot+1,r);
    };
    
    solve(solve,1,n+1);
    
    cout<<"-1 -1"<<endl;
}

int main(){
    int t=1;
    //cin>>t;
    for(int i=1;i<=t;i++)solve(i);
    
    return 0;
}