216. Text Message Decoder (T9 Style)

Write a function solve that decodes old phone keypad text input. Each number represents letters: 2=ABC, 3=DEF, 4=GHI, 5=JKL, 6=MNO, 7=PQRS, 8=TUV, 9=WXYZ. Multiple presses select the letter (22=B, 777=R). Space separates different letters on same key.

Example:
Input: "2 22 222"
Output: "ABC"

Run this challenge interactively in Python or JavaScript when the app loads.