#include <iostream>
#include <algorithm>
#include <iomanip>
#include <vector>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <tuple>
#include <cmath>
#include <numeric>
#include <functional>
#include <cassert>
#include <random>

#define debug_value(x) cerr << "line" << __LINE__ << ":<" << __func__ << ">:" << #x << "=" << x << endl;
#define debug(x) cerr << "line" << __LINE__ << ":<" << __func__ << ">:" << x << endl;

template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }

using namespace std;
typedef long long ll;

template<typename T>
vector<vector<T>> vec2d(int n, int m, T v){
    return vector<vector<T>>(n, vector<T>(m, v));
}

template<typename T>
vector<vector<vector<T>>> vec3d(int n, int m, int k, T v){
    return vector<vector<vector<T>>>(n, vector<vector<T>>(m, vector<T>(k, v)));
}

template<typename T>
void print_vector(vector<T> v, char delimiter=' '){
    if(v.empty()) {
        cout << endl;
        return;
    }
    for(int i = 0; i+1 < v.size(); i++) cout << v[i] << delimiter;
    cout << v.back() << endl;
}

random_device rnd;
mt19937 mt(rnd());
uniform_real_distribution<> uni_dist(0.0, 1.0);
normal_distribution<> norm_dist(0.0, 1.0);

int randint(const int l, const int r){
    return mt()%(r - l) + l;
}

double randdouble(const double l, const double r){
    return (r - l) * uni_dist(mt) + l;
}

const double eps = 1e-5;
const double mx = 1222e72;

class Simulator{
    public:
    Simulator(){
        asked = 0;
        x = randdouble(0.0, 1e50);
        x = 2.0;
    }
    bool ask(double q){
        asked++;
        return x <= q;
    }
    void verify(double q){
        double err = (x-q)/x;
        assert(abs(err) <= 1e-5);
        debug_value(q);
        debug_value(err)
        debug_value(asked);
    }
    private:
    double x;
    int asked;
};

// #define DEBUG

void solve(){
    double l = -6.0, r = 76;
#ifdef DEBUG
    auto sim = Simulator();
#endif
    auto ask_le = [&](double x){
        chmin(x, mx);
    #ifdef DEBUG
        return sim.ask(x);
    #else
        printf("? %.10f\n", x);
        fflush(stdout);
        string s; cin >> s;
        assert(s == "Yes" || s == "No");
        return s[0] == 'Y';
    #endif
    };
    auto verify = [&](double x){
        chmin(x, mx);
    #ifdef DEBUG
        sim.verify(x);
    #else
        printf("! %.10f\n", x);
        fflush(stdout);
    #endif
    };
    int rem = 24;
    while(rem--){
        double x = (l+r)/2;
        if(ask_le(pow(10.0, x))){
            r = x;
        }else{
            l = x;
        }
    }
    double x = (l+r)/2;
    verify(pow(10.0, x));
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << setprecision(10) << fixed;
    cerr << setprecision(10) << fixed;
    int t; cin >> t;
    while(t--) {
        solve();
    }
}