def ii():
    S = input()
    return map(int,S.split()) if " " in S else int(S)
def ai(N = 0):
    return [list(map(int,input().split())) for _ in range(N)] if N!= 0 else list(map(int,input().split()))
def yn(BOOL):
    print("Yes" if BOOL==1 else "No")

import sys,math,heapq,bisect

from collections import defaultdict

lower = 0
upper = pow(10,9)

for i in range(29):
    mid = (lower+upper)//2
    print(mid)
    r = ii()
    if r == 0:
        lower = mid
    else:
        upper = mid
print(lower)

# N,M = ii()
# ans= 0

# for _ in range(N):
#     S,R = input().split()
#     S = list(S)
#     R = int(R)
#     if R>=1200:
#         for i in range(4):
#             if S[i] == 'x':
#                 ans+=1
#                 break
# print(ans)