#include <bits/stdc++.h>

using namespace std;


typedef long long                               ll;
typedef unsigned long long                      ull;
#define int                                     long long
#define itn                                     int
#define endl                                    '\n'
#define Endl                                    endl
#define ednl                                    endl
#define al(a)                                   (a).begin(),(a).end()
#define all(a)                                  (a).begin()+1,(a).end()
#define debug(x)                                {cerr<<"ss:"<<x<<endl;}
#define qdebug(x)                               {cerr<<"ss:";for(auto i:x)cout<<i<<" ";cout<<endl;}
#define lowbit(x)                               (x&-x)
#define vi                                      vector<int>
#define pii                                     pair<int,int>
#define pb                                      push_back
#define fs                                      first
#define sc                                      second

constexpr long long maxlonglong = 9223372036854775807;   //9e18
constexpr int maxint = 2147483647;      //2e9
constexpr int INF = 0x7f7f7f7f7f7f7f7f; //2139062143^2
constexpr int M = 1e9 + 7;
constexpr int mod =  998244353;
constexpr int hs = 0x1F351F35; // good hash number.
const double pi = acos(-1.0);
const double eps = 1e-15;
vector<int> input(int n){vector<int> a(n+1);for(int i=1;i<=n;i++)cin>>a[i];return a;}
mt19937_64 rnd(time(0));


constexpr int N=1231564;

int ask(int u,int v){
    int res;
    cout<<"? "<<u<<" "<<v<<endl;
    cout.flush();
    cin>>res;
    return res;
}

inline void solve(){
    int n;cin>>n;
    int t=0;
    for(int i=1;i<=n/2;i++){
        if(ask(i,n+1-i)){
            t=i;
            break;
        } 
    }
    if(!t&&n%2){
        if(ask(1,(n+1)/2)){
            t=(n+1)/2;
        }
    }
    if(t==0){
        cout<<"! "<<1<<endl;
    }
    else{
        int u=t,v;
        if(u==(n+1)/2)v=1;
        else v=(n+1)-u;
        for(int i=1;i<=n;i++)if(u!=i&&v!=i){
            t=i;
            break;
        }
        if(ask(u,t)){
            int x;
            for(int i=1;i<=n;i++)if(u!=i&&v!=i&&t!=i){
                x=i;
                break;
            }
            if(ask(u,x)){
                cout<<"! "<<2<<endl;
            }
            else cout<<"! "<<1<<endl;
        }
        else if(ask(v,t)){
            int x;
            for(int i=1;i<=n;i++)if(u!=i&&v!=i&&t!=i){
                x=i;
                break;
            }
            if(ask(v,x)){
                cout<<"! "<<2<<endl;
            }
            else cout<<"! "<<1<<endl;
        }
        else cout<<"! "<<1<<endl;

    }
    cout.flush();
}





signed main()
{
    //freopen("E:\work tool\code document\data\input.in", "r", stdin);
	//freopen("E:\work tool\code document\data\output.out", "w", stdout);
    // ios::sync_with_stdio(false);
    // ios_base::sync_with_stdio(false);
    // cin.tie(0);
    // cout.tie(0);    //关闭同步  如果使用 则不要使用<cstdio>
    cout << fixed << setprecision(20);
    int T=1;
    // cin>>T;
    while(T--){
        solve();
    }
    return 0;
}