Flatten Dictionary

You are given a nested dictionary d and a separator string s. Your task is to flatten the dictionary by concatenating nested keys into a single key using the separator. More formally, for a nested key sequence \(k_1, k_2, \dots, k_n\) with value \(v\), the resulting dictionary should have an entry with key \(k_1 s k_2 s \dots s k_n\) and value \(v\). Note that if a nested dictionary is empty, it should be skipped.

For example, if \(d = {"a":1, "b": {"c": 2, "d": {"e": 3}}}\) and the separator is ., the flattened dictionary is \( {"a":1, "b.c":2, "b.d.e":3} \).

The input is provided via standard input (stdin) and the flattened dictionary must be output in JSON format on standard output (stdout).

inputFormat

The input consists of two parts provided through stdin:

1. The first line contains the separator string s.
2. The remaining lines form a JSON string representing the dictionary d.

You can assume that the JSON represents an object whose values are either integers or nested objects.

outputFormat

Output to stdout a single line containing the flattened dictionary in JSON format.

.
{"a": 1, "b": {"c": 2, "d": {"e": 3}}}

{"a":1,"b.c":2,"b.d.e":3}