How many groups are there in the regular expression d4-d2-ddA1B4C5D3

There are 3 groups in the regular expression (\d{4})-(\d{2}-(\d\d)).

Group 1: (\d{4}) - matches any 4 consecutive digits Group 2: (\d{2}-(\d\d)) - matches 2 consecutive digits, followed by a hyphen, and then 2 more consecutive digits Group 3: (\d\d) - matches any 2 consecutive digits within the second group