Different Neighbors (22)

Instruction:

Place a digit from 1-4 into each cell, exactly one digit per cell. Adjacent cells (including diagonally-adjacent cells) must not contain the same digit. Some digits are already given for you.

Reference: WPF (1)

Examples:

WPF Puzzle GP 2015 - Round 1 (80)

WPF Puzzle GP 2017 - Round 7A (24)

Child puzzles:
Numbers not touching