Byteasar is a ranger who works in the Arrow Cave - a famous rendezvous destination among lovers. The cave consists of chambers connected with one-way corridors. In each chamber exactly one outgoing corridor is marked with an arrow. Every corridor leads directly to some (not necessarily different) chamber.
The enamoured couples that agree to meet in the Arrow Cave are notorious for forgetting to agree upon specific chamber, and consequently often cannot find their dates. In the past this led to many mix-ups and misunderstandings\dots But ever since each chamber is equipped with an emergency telephone line to the ranger on duty, helping the enamoured find their dates has become the rangers' main occupation.
The rangers came up with the following method. Knowing where the enamoured are, they tell each of them how many times they should follow the corridor marked with an arrow in order to meet their date. The lovers obviously want to meet as soon as possible - after all, they came to the cave to spend time together, not to wander around alone! Most rangers are happy to oblige: they do their best to give each couple a valid pair of numbers such that their maximum is minimal.
But some rangers, among their numbers Byteasar, grew tired of this extracurricular activity and ensuing puzzles. Byteasar has asked you to write a program that will ease the process. The program, given a description of the cave and the current location of k couples, should determine k pairs of numbers xi and yi such that
There are multiple test cases, terminated by EOF.
For each test case, In the first line of the standard input there are two positive integers n and k (1<=n<=500000, 1<=k<=500000), separated by a single space, that denote the number of chambers in the Arrow Cave and the number of couples who want to find their dates, respectively. The chambers are numbered from 1 to n, while the enamoured couples are numbered from 1 to k.
The second line of input contains n positive integers separated by single spaces: the i-th such integer determines the number of chamber to which the corridor marked with an arrow going out of chamber i leads.
The following k lines specify the queries by the separated couples. Each such query consists of two positive integers separated by a single space - these denote the numbers of chambers where the lovers are - first him, then her.
For each query output the corresponding xi and yi in a line.
12 5 4 3 5 5 1 1 12 12 9 9 7 1 7 2 8 11 1 2 9 10 10 5 12 5 4 3 5 5 1 1 12 12 9 9 7 1 7 2 8 11 1 2 9 10 10 5
2 3 1 2 2 2 0 1 -1 -1 2 3 1 2 2 2 0 1 -1 -1
Migrated from old NTUJ.
IPSC 2012
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