codeforces#P900B. Position in Fraction
Position in Fraction
Description
You have a fraction 
. You need to find the first occurrence of digit c into decimal notation of the fraction after decimal point.
The first contains three single positive integers a, b, c (1 ≤ a < b ≤ 105, 0 ≤ c ≤ 9).
Print position of the first occurrence of digit c into the fraction. Positions are numbered from 1 after decimal point. It there is no such position, print -1.
Input
The first contains three single positive integers a, b, c (1 ≤ a < b ≤ 105, 0 ≤ c ≤ 9).
Output
Print position of the first occurrence of digit c into the fraction. Positions are numbered from 1 after decimal point. It there is no such position, print -1.
Samples
1 2 0
2
2 3 7
-1
Note
The fraction in the first example has the following decimal notation: 
. The first zero stands on second position.
The fraction in the second example has the following decimal notation: 
. There is no digit 7 in decimal notation of the fraction.