#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<ll,ll> P;
#define REP(i,n) for(ll i=0;i<ll(n);i++)













int main(void){
	cin.tie(nullptr);  ios_base::sync_with_stdio(false);
	ll i,j;



	ll N,M,L;
	cin >> N >> M >> L;


	if(L==0){
		cout << "? " << N << ' ' << 1 << endl;
		cout.flush();

		ll a;
		cin >> a;

		cout << "! " << a << endl;
		cout.flush();

	}else{


	ll x=N;
	for(i=1;i<=L;i++){

		cout << "? " << x << ' ' <<  M << endl;
		cout.flush();

		ll a;
		cin >> a;

		x=a;

	}


	cout << "! " << x << endl;
	cout.flush();


	}









	return 0;

}