Checking JSON for correctness

PHP Easy json

Task «Checking JSON for correctness»

Write a program that reads a string containing JSON and checks whether it is valid JSON. If the string is valid JSON, output 'valid', otherwise output 'invalid'. The string may contain spaces and line breaks. It is guaranteed that the length of the string does not exceed 1000 characters.

Input Format

One line containing JSON.

Output Format

One line: 'valid' or 'invalid'.

Examples

Example 1

INPUT

2
A B 500 1
C D 500 2

OUTPUT

invalid

Example 2

INPUT

{"key": "value"}

OUTPUT

valid

Example 3

INPUT

0

OUTPUT

valid

main.php