Flatten Nested Dictionary

Given a JSON object representing a dictionary, possibly containing nested dictionaries, your task is to flatten it. The flattening process involves concatenating keys from the nested dictionaries using a dot ('.') as a separator. For example, a nested key {"a": {"b": 1}} should be flattened to {"a.b": 1}. This problem tests your ability to recursively process data structures.

Note: Non-dictionary values such as numbers, strings, or arrays should remain unchanged.

inputFormat

The input is provided as a single line from standard input (stdin). It is a valid JSON object representing a dictionary which may include nested dictionaries.

outputFormat

Output the flattened dictionary as a JSON object in a single line to standard output (stdout). Nested keys are concatenated with a dot ('.').

{"a": 1, "b": 2}

{"a":1,"b":2}