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Problem
A tree with `n` nodes numbered from `1` to `n` is represented by
the parent array `t`, where `t[i]` is the parent of node `i`, and
`t[i] = 0` means that node `i` is the root of the tree.
Two nodes `x` and `y` are also read (not necessarily distinct). Print
the **lowest common ancestor** of `x` and `y`: the deepest node that
appears on both the path from `x` to the root and the path from `y`
to the root.
Convention: a node is its own ancestor. If `x = y`, the answer is `x`.
If `x` is an ancestor of `y`, the answer is `x`.
Input format
Input
input.txt
The first line contains three natural numbers `n`, `x`, and `y`, separated by spaces. The second line contains the `n` values of the parent array, separated by spaces. - `1 <= n <= 100` - `1 <= x, y <= n` - the array describes a valid tree
Output format
Output
output.txt
The program prints a single natural number: the index of the lowest common ancestor of nodes `x` and `y`.
Example
input
7 1 6 2 4 4 0 4 5 5
output
4
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Sample cases (from the problem)
Sample Case 1
Input
7 1 6 2 4 4 0 4 5 5
Expected output
4
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