import std.conv, std.functional, std.range, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.bitmanip, std.complex, std.container, std.math, std.mathspecial, std.numeric, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }
real readReal() { return readToken.to!real; }

bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }

int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; }
int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); }
int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); }


bool Ask(real y) {
  writefln("? %.20f", y);
  stdout.flush;
  const res = readToken();
  if (res == "-1") {
    import core.stdc.stdlib;
    exit(0);
  }
  return (res == "Yes");
}
void Answer(real x) {
  writefln("! %.20f", x);
  stdout.flush;
}


enum N = 24;
enum EPS = 1e-5L;
enum L = 12.22e74L;

real get(real t) {
  return (t < 0.0L) ? (1.0L + EPS * t) : pow(1.0L + EPS, t);
}

void main() {
  const numCases = readInt();
  foreach (caseId; 0 .. numCases) {
    real lo = -1.0L / EPS, hi = log(L) / log(1.0L + EPS);
    foreach (iter; 0 .. N) {
      const mid = (lo + hi) / 2.0L;
      const y = get(mid);
      (Ask(y) ? hi : lo) = mid;
    }
    const x = get((lo + hi) / 2.0L);
    Answer(x);
  }
}