def binary_search(f):
    left,right=1,10**6+1
    while right-left>1:
        mid=(right+left)//2
        if f(mid):
            right=mid
        else:
            left=mid
    return left
a = 21
def ask(x,x_d):
    print('?', x_d)
    return int(input())
    if abs(a-x) >= abs(a-x_d):
        print("1")
        return 1
    return 0

def f(x):
    global s
    if s < 0:
        s_d = s+abs(s-x)*2
    else:
        s_d = s-abs(s-x)*2-1
    r=ask(s,s_d)
    s = s_d
    if r == -1:
        assert False
    if r == 1:
        if s < 0:
            return True
        else:
            return False
    else:
        if s < 0:
            return False
        else:
            return True



s = 10**7
print('?', s)
a=binary_search(f)
print('!', a)