How long is the largest group of numbers?

The title is the problem's question.

The process is:

• the base is 10
• the number of digits summed is 2
• make a list of the integers from 0 to base ^ digits -1 called input
• set groups to an empty list
• while the length of the input is greater than 0 do until matching end of while
• set v to the first element of input
• set input to the remainder of input
• set group to the list of the integer digits of v using the base base zero padded on the left to the length digits as necessary
• set d to the sum of the last digits integers in groups modulus base
• append d to the end of the group
• while the first digits integers of group do not match the last digits integers of group do until matching *end of while
• set v to the last digits of group using base base (consider the last digits integers of group as the digits of a digits digit base base integer)
• remove from input any integers that match v
• set d to the sum of the last digits integers in groups modulus base (add up the digits of v and set d to the modulus base (take the last digit))
• append d to the end of the group
• end of while
• after dropping the last digits values from group , append group as a value to groups
• end of while

What is the length of the longest value within the list groups ?