Grouping by property using Mongo repository

I use the Java Spring MongoDB repository in my project.

I have this collection in MongoDB called Info:

{ "_id" : 1, "hosting" : "hostgator.com", count:7 }
{ "_id" : 2, "hosting" : "aws.amazon.com", count:7}
{ "_id" : 3, "hosting" : "aws.amazon.com", count:3}
{ "_id" : 4, "hosting" : "hostgator.com", count:5 }
{ "_id" : 5, "hosting" : "aws.amazon.com", count:1 }
{ "_id" : 6, "hosting" : "cloud.google.com", count:1 }
{ "_id" : 7, "hosting" : "aws.amazon.com", count:5 }
{ "_id" : 8, "hosting" : "hostgator.com", count:2 }
{ "_id" : 9, "hosting" : "cloud.google.com", count:3 }
{ "_id" : 10,"hosting" : "godaddy.com", count:7 }
...
{ "_id" : 100, "hosting" : "godaddy.com", count:5 }

Here is DTO definition:

public class Info{
    public int _id;
    public String hosting;
    public int count;
}

I need to write a query and to get from the database all values of count property and remove the duplications. For example, the result that I expect according to the collection above is:

List<int> counts = [1,2,3,5,7];

For this purpose I use the aggregation group method and MongoTemplate:

        GroupOperation groupOperation = Aggregation.group("count");
        Aggregation aggregation = Aggregation.newAggregation(groupOperation);
        var result = template.aggregate(aggregation, Info.class,  Info[].class);
        System.out.println(result.getMappedResults());

But the result that I get is an empty array - [].

Why I don't get the expected result?