VBA code to find duplicate and combine their values

Hello,
I´m looking for macro that goes thru data in one column at sheet 1 to find duplicates, then export duplicate text to another sheet and combine their values as text.

for example:

Inbut data
A____________B
CZ___________1
EU___________9
CZ___________13
CZ___________23
EU___________31

output on another sheet:
A__________B
CZ_________1, 13, 23
EU_________9, 31


Thank you for help