#include <cstdio>
#include <cstring>
#include <iostream>
#include <string>
#include <cmath>
#include <bitset>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <algorithm>
#include <complex>
#include <unordered_map>
#include <unordered_set>
#include <random>
#include <cassert>
#include <fstream>
#include <utility>
#include <functional>
#include <time.h>
#include <stack>
#include <array>
#include <list>
#include <atcoder/all>
#define popcount __builtin_popcount
using namespace std;
using namespace atcoder;
typedef long long ll;
typedef pair<int, int> P;
using mint=modint998244353;
bool query(double x){
  cout<<"? "<<x<<endl;
  string res;
  cin>>res;
  return res=="Yes";
}
int main()
{
  int t;cin>>t;
  while(t--){
    double x0=167.772;
    if(query(x0)){
      double l=0, r=x0;
      for(int i=0; i<23; i++){
        double m=(l+r)/2;
        if(query(m)){
          r=m;
        }else{
          l=m;
        }
      }
      cout<<"! "<<(l+r)/2<<endl;
    }else{
      double l=x0, r=1.222e75;
      for(int i=0; i<23; i++){
        double m=sqrt(l*r);
        if(query(m)){
          r=m;
        }else{
          l=m;
        }
      }
      cout<<"! "<<sqrt(l*r)<<endl;
    }
  }
    return 0;
}