#include <bits/stdc++.h>
using namespace std;
static const double EPS = 1e-10;
template <typename T, typename S>
vector<T>& operator<<(vector<T>& a, S b) {
  a.push_back(b);
  return a;
}
template <typename T>
void operator>>(vector<T>& a, int b) {
  while (b--)
    if (!a.empty()) a.pop_back();
}
bool isprime(int n) {
  if (n < 2) return false;
  for (int i = 2; i * i <= n; i++)
    if (n % i == 0) return false;
  return true;
}
long long b_pow(long long x, long long n) {
  return n ? b_pow(x * x, n / 2) * (n % 2 ? x : 1) : 1ll;
}
string itos(int n) {
  stringstream ss;
  ss << n;
  return ss.str();
}
long long in() {
  long long n;
  scanf("%lld", &n);
  return n;
}
int main() {
  int a, b, n;
  cin >> a >> b >> n;
  int mod = a % b;
  string answer;
  stringstream ss;
  ss << a;
  answer = ss.str();
  a %= b;
  while (n--) {
    int f = 1;
    for (int i = 0; i < 10; i++) {
      if ((a * 10 + i) % b == 0) {
        f = 0;
        a = a * 10 + i;
        a %= b;
        answer += i + '0';
        break;
      }
    }
    if (f) {
      cout << -1 << endl;
      return 0;
    }
  }
  cout << answer << endl;
}
