java – RegExp for matching a substring in a Json type String

I need to match an specific sentence from a json file, the string would be this: json = Files.readString(path)

The idea is to match this in the string: ],"count":int}{"contacts":[ with int taking diferent values.

The regex expression (for Java) that i got is: String regex = "],\"count\":\\d*\}\{\"contacts\":\["

But im not gettin any matches, what´s wrong with my regex expression? It’s probably that the sentence is completely wrong since im not really familiar with regular expressions.

Thanks