CF260A Adding Digits

Vasya has got two number: $ a $ and $ b $ . However, Vasya finds number $ a $ too short. So he decided to repeat the operation of lengthening number $ a $ $ n $ times. One operation of lengthening a number means adding exactly one digit to the number (in the decimal notation) to the right provided that the resulting number is divisible by Vasya's number $ b $ . If it is impossible to obtain the number which is divisible by $ b $ , then the lengthening operation cannot be performed. Your task is to help Vasya and print the number he can get after applying the lengthening operation to number $ a\ n $ times.

The first line contains three integers: $ a,b,n\ (1

In a single line print the integer without leading zeros, which Vasya can get when he applies the lengthening operations to number $ a\ n $ times. If no such number exists, then print number -1. If there are multiple possible answers, print any of them.