CF900B Position in Fraction

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\le a

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.

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.