A11376. 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 $a$ , $b$ , $c$ ( $1\le a<b\le 10^{5}$ , $0\le c\le 9$ ).

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.

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.