Starting at line 158, we analyze each pair of numbers to see if they fit the criteria. 68 is too large; 04 is the first one that works. 65 is too large; 40 is the second one that works. 31 is the third one that works. 75 and 84 are too large; 00 is not within the limits; 66 is too large; 37 is the fourth one that works.