#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b, n, i, x, m;
  char num[200000];
  scanf("%d %d %d", &a, &b, &n);
  x = a;
  m = 0;
  while (x) {
    num[m++] = x % 10 + '0';
    x /= 10;
  }
  num[m] = 0;
  reverse(num, num + m);
  a %= b;
  while (true) {
    for (i = 0; i < 10; ++i) {
      x = 10 * a + i;
      if (x % b == 0) {
        a = x % b;
        num[m++] = '0' + i;
        i = -1;
        --n;
        if (n == 0) {
          num[m] = 0;
          printf("%s", num);
          return 0;
        }
        continue;
      }
    }
    printf("-1");
    return 0;
  }
}
