#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
using ll = long long;
constexpr int INF = 0x3f3f3f3f;
constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL;
constexpr double EPS = 1e-8;
constexpr int MOD = 1000000007;
// constexpr int MOD = 998244353;
constexpr int DY[]{1, 0, -1, 0}, DX[]{0, -1, 0, 1};
constexpr int DY8[]{1, 1, 0, -1, -1, -1, 0, 1}, DX8[]{0, -1, -1, -1, 0, 1, 1, 1};
template <typename T, typename U> inline bool chmax(T& a, U b) { return a < b ? (a = b, true) : false; }
template <typename T, typename U> inline bool chmin(T& a, U b) { return a > b ? (a = b, true) : false; }
struct IOSetup {
  IOSetup() {
    std::cin.tie(nullptr);
    std::ios_base::sync_with_stdio(false);
    std::cout << fixed << setprecision(20);
  }
} iosetup;

constexpr int Q = 24;
constexpr long double M = 12.22 * 1e74;

bool query(long double y) {
  cout << "? " << y << endl;
  string s; cin >> s;
  assert(s != "-1");
  return s == "Yes";
}

// https://codeforces.com/blog/entry/49189
// https://twitter.com/maspy_stars/status/1369696139683844097
void solve() {
  if (query(1)) {
    long double lb = 0, ub = 1;
    REP(_, Q - 1) {
      const long double mid = (lb + ub) / 2;
      (query(mid) ? ub : lb) = mid;
    }
    cout << "! " << ub << endl;
  } else {
    long double lb = 1, ub = M;
    REP(_, Q - 1) {
      const long double mid = sqrtl(lb * ub);
      (query(mid) ? ub : lb) = mid;
    }
    cout << "! " << ub << endl;
  }
}

int main() {
  int t; cin >> t;
  while (t--) solve();
  return 0;
}