Step 1: Divide the number into separate digits:
19903 => 1 9 9 0 3
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
1 to 9 = 8
9 to 9 = 0
9 to 0 = 9
0 to 3 = 3
3 to 1 = 2
Step 3: Combine the filters to a string:
8 0 9 3 2 = 80932