Step 1: Divide the number into separate digits:
12354 => 1 2 3 5 4
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
1 to 2 = 1
2 to 3 = 1
3 to 5 = 2
5 to 4 = 1
4 to 1 = 3
Step 3: Combine the filters to a string:
1 1 2 1 3 = 11213