#include using namespace std; typedef long long ll; #define REP(i,n) for(int i=0; i #define VP vector> #define VPP vector>> #define VLL vector #define VVI vector> #define VVLL vector> #define VC vector #define VS vector #define VVC vector> #define VB vector #define VVB vector> #define fore(i,a) for(auto &i:a) typedef pair P; template using min_priority_queue = priority_queue, greater>; template bool chmax(T &a, T b) { if (a < b) { a = b; return true; } return false; } template bool chmin(T &a, T b) { if (a > b) { a = b; return true; } return false; } const int INF = 1 << 29; const ll INFL = 1LL << 60; const ll mod = 998244353; const int MAX = 1010000; long long fac[MAX], finv[MAX], inv[MAX]; void COMinit() { fac[0] = fac[1] = 1; finv[0] = finv[1] = 1; inv[1] = 1; for (int i = 2; i < MAX; i++) { fac[i] = fac[i - 1] * i % mod; inv[i] = mod - inv[mod%i] * (mod / i) % mod; finv[i] = finv[i - 1] * inv[i] % mod; } } long long COM(int n, int k) { if (n < k) return 0; if (n < 0 || k < 0) return 0; return fac[n] * (finv[k] * finv[n - k] % mod) % mod; } long long modinv(long long a, long long m) { long long b = m, u = 1, v = 0; while (b) { long long t = a / b; a -= t * b; swap(a, b); u -= t * v; swap(u, v); } u %= m; if (u < 0) u += m; return u; } int main(){ int ok = 1001; int ng = -1; while (ok - ng > 1) { int mid = (ok + ng) / 2; string s; cout << "? " << mid << endl; cin >> s; if (s == "safe") { ng = mid; continue; } cout << "? " << mid + 1 << endl; cin >> s; if (s == "safe") { ng = mid + 1; } else { ok = mid; } } string s; cin >> s; if (s == "safe") { cout << "! " << ok << endl; } else cout << "! " << ng << endl; }