B"The Central Company has an office with a sophisticated security system. There are 10^6 employees, numbered from 1 to 10^6 . The security system logs entrances and departures. The entrance of the i -th employee is denoted by the integer i , while the departure of the i -th employee is denoted by the integer -i . The company has some strict rules about access to its office: Any array of events satisfying these conditions is called a valid day. Some examples of valid or invalid days: There are n events a_1, a_2, ldots, a_n , in the order they occurred. This array corresponds to one or more consecutive days. The system administrator erased the dates of events by mistake, but he didn't change the order of the events. You must partition (to cut) the array a of events into contiguous subarrays, which must represent non-empty valid days (or say that it's impossible). Each array element should belong to exactly one contiguous subarray of a partition. Each contiguous subarray of a partition should be a valid day. For example, if n=8 and a=[1, -1, 1, 2, -1, -2, 3, -3] then he can partition it into two contiguous subarrays which are valid days: a = [1, -1~ boldsymbol{|}~ 1, 2, -1, -2, 3, -3] . Help the administrator to partition the given array a in the required way or report that it is impossible to do. Find any required partition, you should not minimize or maximize the number of parts. The first line contains a single integer n ( 1 <= n <= 10^5 ). The second line contains n integers a_1, a_2, ldots, a_n ( -10^6 <= a_i <= 10^6 and a_i neq 0 ). If there is no valid partition, print -1 . Otherwise, print any valid partition in the following format: If there are many valid solutions, you can print any of them. You don't have to minimize nor maximize the number of days. In the first example, the whole array is a valid day. In the second example, one "...