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

int tag;

void solve(int l,int r,int lst)
{
    if(tag==1)
    {
        return;
    }
    int mid,x,y;
    mid=(l+r)>>1;
    if(l==r)
    {
        tag=1;
        cout<<"! "<<r;
        cout.flush();
        return;
    }
    
    cout<<"? "<<mid<<"\n";
    cin>>x;
    cout.flush();
    if(x==lst)
    {
        tag=1;
        cout<<"! "<<mid;
        cout.flush();
        return;
    }
    
    cout<<"? "<<r<<"\n";
    cin>>y;
    cout.flush();
    if(y==x)
    {
        tag=1;
        cout<<"! "<<r;
        cout.flush();
        return;
    }
    cout<<x<<" "<<y<<endl;
    if(x<y)
    {
        solve(l,max(l,mid-1),y);
    }
    else
    {
        solve(min(r-1,mid+1),r-1,y);
    }
    return;
}

int main()
{
    int n;
    cin>>n;
    tag=0;
    solve(1,n,0);
    
    return 0;
}