# SPOJ PERMUT2

## Summary

Identify whether the inverse permutation of a given permutation of digits is ambiguous.

## Explanation

The inverse permutation is one where the i-th number is the position of the integer i in the permutation. It is ambiguous if it is identical to the normal representation of the permutation. For example, if { 2, 3, 4, 5, 1 } is a permutation, then it's inverse is { 5, 1, 2, 3, 4 } and in this case is not ambiguous.

## Implementation

Plenty of time is allowed for this problem. A brute force comparison of one array with its inverse will satisfy the judge.

## Input

The first line of the input is an integer ${\displaystyle 1\leq n\leq 100000}$ representing the length of the permutation to follow. The next line contains ${\displaystyle n}$ integers representing the permutation. More test cases may follow. The input is terminated by a single 0.

4
1 4 3 2
5
2 3 4 5 1
1
1
0


## Output

ambiguous
not ambiguous
ambiguous