Write a function that determines if nine-digit number is divisible by 13 using the following method:

a. form alternating sums of blocks of three numbers from the right and moving towards the left; this should reduce the number into three digits. For 245,347,296: 296-347+245 = 194 b. from the three digit number formed from the previous step, multiply the last digit by 4 and add this to the rest truncate of the number; this should result to a two digit number repeat the step if it does not. For 194: the last digit is 4; 4 times 4 equals 16, then add this to 19 (the remaining digits of 194); thus, 16 plus 19 equals 35. c. if this number is divisible by 13 (the two-digit multiples of 13 are 13, 26, 39, 52, 65, 78, and 91), the input number is divisible by 13