import sys
readline = sys.stdin.readline
write = sys.stdout.write
flush = sys.stdout.flush

# クエリ: "? x1 x2" を出力
def query(x):
    write("? %d\n" %x)
    flush()
    # ジャッジから返される値を取得
    return readline().strip()

# 回答: "! x" を出力
def answer(x):
    write("! %d\n" % x)
    flush()
    # 即時終了
    exit(0)

def check(target):
  #checkする処理
  s = query(target)
  if s=='safe':
    return True
  t = query(target-1)
  if t=='safe':
    return True
  return False

low,high = 0,10**3
mid = (low+high)//2
while high-low>1:
  if check(mid):
    low = mid
  else:
    high = mid
  mid = (low+high)//2
if query(mid)=='safe':
  answer(mid)
else:
  answer(mid-1)