func main()
	const m: int :: 30
	
	var ok: int :: 1
	var ng: int :: 10 ^ 9 + 1
	for(1, m - 1)
		var x: int :: (ok + ng) / 2
		do cui@print("\{x}\n")
		do cui@flush()
		var r: int :: cui@inputInt()
		
		if(r = 1)
			do ok :: x
		else
			do ng :: x
		end if
	end for
	var ans: int :: ok
	
	do cui@print("\{ans}\n")
end func