/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
import java.time.* ;
import java.util.stream.* ;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
 
List< String > inputs = List.of( "2021-07-01", "2021-08-20", "2021-08-25", "2021-09-05", "2022-01-06", "2022-06-07" );
 
Map< YearMonth , Long > monthCounts = 
    inputs
        .stream()
        .map( input -> LocalDate.parse( input ) )
        .collect(
            Collectors.groupingBy( 
                           YearMonth :: from ,
                           Collectors.counting()
            )
        )
;
 
System.out.println( monthCounts ) ;
 
	}
}

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