#include <bits/stdc++.h>
using namespace std;
#if __has_include(<atcoder/all>)
#include <atcoder/all>
using namespace atcoder;
typedef modint998244353 mint;
#endif
typedef long long  ll;
typedef pair<int,int> pii; typedef pair<ll,ll> pll;
const int INF = 1e9; const long long LINF = 1e18;
const int MOD = 998244353; const int MOD1 = 1e9+7;
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define all(x) x.begin(), x.end()
template<typename T> bool chmin(T& a, T b){if(a > b){a = b; return true;} return false;}
template<typename T> bool chmax(T& a, T b){if(a < b){a = b; return true;} return false;}
void yorn(bool ans){cout << (ans?"Yes":"No") << endl; return;}

// しばらくはsize_tをキャストに任せてみようかな
int main(){
    int n; cin >> n;
    vector<bool> p(n,true); // probably

    int x = 0,y = 1;
    while(1){
        cout << "? " << x << ' ' << y << endl;
        int z; cin >> z;
        if(z==x){
            cout << "! " << y << endl; return 0;
        }
        if(z==y){
            cout << "! " << x << endl; return 0;
        }

        p.at(x) = false; p.at(y) = false;
        if(p.at(z)==true) x = z;
        else{
            rep(i,n){
                if(p.at(i)==true){x = i; break;}
            }
            
        }
        rep(i,n){
            if(i==n-1){cout << "! " << x << endl; return 0;}
            if(i==x) continue;
            if(p.at(i)==true){y = i; break;}
        }
    }
    return 0;
}