def query_ask(y):
    print(f"? {y}", flush=True)
    if DEBUG:
        return  y <= X
    else:
        return int(input())

def query_ans(x):
    print(f"! {x}", flush=True)
    

DEBUG = 0
if DEBUG:
    print("DEBUG MODE!")
    X = 10

from bisect import bisect_left

def reverse_result(y):
    return ~query_ask(y)

ans = bisect_left(range(10**9+1),1,key=reverse_result)
query_ans(ans)