import sys
readline=sys.stdin.readline

def Interactive(*query):
    print(*query)
    sys.stdout.flush()
    return input()

def Bisect_Int(ok,ng,is_ok):
    while abs(ok-ng)>1:
        mid=(ok+ng)//2
        if is_ok(mid):
            ok=mid
        else:
            ng=mid
    return ok

def is_ok(x):
    return int(Interactive("?",x))

ans=Bisect_Int(1,1<<30,is_ok)
print("!",ans)