#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;
using namespace std;
#define rep(i,n) for(int i=0;i<(n);i++)
#define Inf 1000000001

void answer(int n){
	cout<<"! 1 "<<n<<endl;
	exit(0);
}

int query(int L,int R){
	int x,y;
	if(L==1)x = 0;
	else {
		cout<<"? "<<L-1<<endl;
		int ret;
		cin>>ret;
		x = ret;
	}
	cout<<"? "<<R<<endl;
	cin>>y;
	return y-x;
}


int main(){
	int N;
	cin>>N;
	int L = 1,R = N-2;
	while(R<=N){
		int q = query(L,R);
		if(q==(N-2)/2){
			cout<<"! "<<L<<' '<<R<<endl;
			return 0;
		}
		L++;
		R++;
	}
	
	cout<<"! "<<3<<' '<<N-2<<endl;
	
	return 0;
}