func main()
	var x: int
	block
		var ok: int :: -1
		var ng: int :: 100000
		while((ok - ng).abs() > 1)
			var mid: int :: (ok + ng) / 2
			var a: int :: f(mid, -1)
			var b: int :: f(mid + 1, -1)
			if(b < a)
				do ok :: mid
			else
				do ng :: mid
			end if
		end while
		do x :: ok
	end block
	var y: int
	block
		var ok: int :: -1
		var ng: int :: 100000
		while((ok - ng).abs() > 1)
			var mid: int :: (ok + ng) / 2
			var a: int :: f(-1, mid)
			var b: int :: f(-1, mid + 1)
			if(b < a)
				do ok :: mid
			else
				do ng :: mid
			end if
		end while
		do y :: ok
	end block
	
	do cui@print("\{x} \{y}\n")
	
	func f(x: int, y: int): int
		do cui@print("\{x} \{y}\n")
		do cui@flush()
		ret cui@inputInt()
	end func
end func