#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pb(a) push_back(a)
#define pp pop_back
#define mp(a, b) make_pair(a, b)
int32_t main(){
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
int n, len=1; bool a, b=0;
cin >> n;
for (int i=2; i<=n; i++) {
cout << "? " << i-len << " " << i << "\n";
fflush(stdout);
cin >> a;
if (i!=len+1) {
cout << "? " << i-len-1 << " " << i << "\n";
fflush(stdout);
cin >> b;
}
if (b) len+=2;
else if (a) len++;
}
cout << "! " << len << "\n";
return 0;
}
