//#define _GLIBCXX_DEBUG #include #include using namespace std; using namespace atcoder; using ll = long long; using mint = modint1000000007; #define rep(i,n) for (int i = 0; i < n; i++) #define rrep(i,n) for (int i = n-1; i >= 0; i--) #define rep2(i,a,b) for (int i = a; i < b; i++) #define rrep2(i,a,b) for (int i = a-1; i >= b; i--) #define all(v) v.begin(),v.end() #define rall(v) v.rbegin(),v.rend() #define minv(v) *min_element(all(v)) #define maxv(v) *max_element(all(v)) template bool chmax(T &a, T b){if (a < b){a = b;return true;} else return false;} template bool chmin(T &a, T b){if (a > b){a = b;return true;} else return false;} template T pow(T x, T y){if (y == 0) return 1.0;T p = pow(x,y/2);if (y%2 == 0) return p*p;else return p*p*x;} int f(int s, int x){ return 2*s-x; } int main(){ int n; cin >> n; int s1, s2; cout << "? " << 1 << endl; cin >> s1; s1 = f(s1,1); cout << "? " << n-1 << endl; cin >> s2; s2 = f(s2,n-1); if (s1 == s2){ cout << "! " << 2 << " " << n-1 << endl; } else if (s1 == 1){ int l = 1, r = n-1; rep(i,18){ int s, k = (l+r)/2; cout << "? " << k << endl; cin >> s; s = f(s,k); if (s == 0){ if (k >= n/2) cout << "! " << 1 << " " << k << endl; else cout << "! " << k/2 << " " << n << endl; return 0; } if (s > 0){ l = k; } else{ r = k; } } } else{ int l = 1, r = n-1; rep(i,18){ int s, k = (l+r)/2; cout << "? " << k << endl; cin >> s; s = f(s,k); if (s == 0){ if (k >= n/2) cout << "! " << 1 << " " << k << endl; else cout << "! " << k << " " << n << endl; return 0; } if (s > 0){ r = k; } else{ l = k; } } } }