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.

瓦西娅有两个数：$a$ 和 $b$。然而，瓦西娅觉得数 $a$ 太短了，因此他决定对数 $a$ 执行 $n$ 次“延长”操作。

一次“延长”操作是指：在该数（十进制表示）的右侧恰好添加一位数字，使得得到的新数能被瓦西娅的数 $b$ 整除。如果无法得到能被 $b$ 整除的数，则该次延长操作无法执行。

你的任务是帮助瓦西娅，输出对数 $a$ 执行 $n$ 次延长操作后所能得到的数。

The first line contains three integers: a, b, n (1 ≤ a, b, n ≤ 105).

第一行包含三个整数：$a$、$b$、$n$（$1 \leq a, b, n \leq 10^5$）。

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.

在一行中输出一个不含前导零的整数，该整数是瓦夏对数字 $a$ 执行 $n$ 次延长操作后所能得到的结果。如果不存在这样的数字，则输出 $-1$。如果存在多个可能的答案，输出其中任意一个即可。