#include<bits/stdc++.h>
using namespace std;
// #define int long long
#define ll long long
#define db double
const int mod=998244353;
const int N=2e5+5;

int ask(int x,int y){
    int tmp;
    cout<<"? "<<x<<" "<<y<<endl;
    cin>>tmp;
    return tmp;
}
void abt(){
    int n;
    cin>>n;
    int t1,t2;
    for(int i=1;i<=n;i+=2){
        int tmp;
        tmp=ask(i,i+1);
        if(tmp==1){
            t1=i;t2=i+1;
            break;
        }
    }
    if(n%2==1){
        int tmp;
        tmp=ask(1,n);
        if(tmp==1){
            t1=1;t2=n;
        }
    }
    int t3,t4;
    if(t1==1&&t2==n){
        t3=2,t4=3;
    }else if(t1>n/2){
        t3=1,t4=2;
    }else{
        t3=n-1,t4=n;
    }
    int jud=0;
    if(ask(t1,t3)){
        if(ask(t1,t4)){
            jud=1;
        }
    }else{
        if(ask(t2,t3)){
            if(ask(t2,t4)){
                jud=1;
            }
        }
    }
    if(jud){
        cout<<"! "<<2<<endl;
    }else{
        cout<<"! "<<1<<endl;
    }

}

signed main(){
    // ios::sync_with_stdio(false);
    // cin.tie(nullptr);cout.tie(nullptr);
    int T=1;
    // cin>>T;
    while(T--) abt();
    return 0;
}