ACM International Collegiate Programming Contest 1989
Northwestern European Regionals
Problem A
Warning: Not all numbers in this problem are decimal numbers!
Multiplication of natural numbers in general is a cumbersome operation.
In some cases however the product can be obtained by moving the last digit
to the front.
Example: 179487 * 4 = 717948
Of course this property depends on the numbersystem you use, in the
above example we used the decimal representation. In base 9 we have a shorter
example:
17 * 4 = 71 (base 9)
as (9 + 7) * 4 = 7 * 9 +1
Input
The input for your program is a textfile. Each line consists of three numbers
separated by a space: the base of the number system, the least significant
digit of the first factor, and the second factor. This second factor is
one digit only hence less than the base. The input file ends with the standard
end-of-file marker.
Output
Your program determines for each input line the number of digits of the
smallest first factor with the rotamultproperty. The output-file is also
a textfile. Each line contains the answer for the corresponding input line.
Sample
Input
10 7 4
9 7 4
17 14 12
Sample
Output
6
4
2