digits
22233344455566677778889999
letters
abcdefghijklmnopqrstuvwxyz
5{.valid
┌─┬──┬───┬───┬──┐
│a│aa│aaa│aam│ab│
└─┴──┴───┴───┴──┘
5{.reps
│2│22│222│226│22│