cnt = 0

def ret2(x):
    print("?",x)
    return int(input())

def ret(ans,cnt,x):
    if x == ans - cnt:
        return 0
    elif x > ans - cnt:
        return -1
    else:
        return 1

def solve():
    cnt = 0
    #r = ret(ans,cnt,100)
    r = ret2(100)
    cnt += 1
    if r == 0:
        print("!",100)
        return
    elif r == -1:
        lb = 10
        ub = 100
        while ub - lb > 0:
            mid = (ub + lb) // 2
            #r = ret(ans,cnt,mid - cnt)
            r = ret2(mid-cnt)
            cnt += 1
            if r == 0:
                print("!",mid)
                return
            elif r == 1:
                lb = mid
            else:
                ub = mid
        return
    else:
        lb = 101
        ub = 10 ** 9 + 1
        while ub - lb > 0:
            mid = (ub + lb) // 2
            #r = ret(ans,cnt,mid - cnt)
            r = ret2(mid-cnt)
            cnt += 1
            if r == 0:
                print("!",mid)
                return
            elif r == 1:
                lb = mid
            else:
                ub = mid

solve()