Get maximum value based on unique values in excel

Get maximum value based on unique values in excel

I have two rows in excel as follows:
row1 row2
1 10
1 22
1 11
1 23
1 14
2 16
2 12
2 10
2 9
How do i write a command to get maximum value from row 2 corresponding to
each unique value in row1.
so here i need to write a command to get 23 and 16