#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b, n;
  cin >> a >> b >> n;
  string st;
  int t = a;
  while (a != 0) {
    st += "0";
    st[st.size() - 1] += a % 10;
    a /= 10;
  }
  reverse(st.begin(), st.end());
  a = t % b;
  for (int i = 0; i < (int)n; i++) {
    t = a;
    bool p = false;
    for (int j = 0; j < (int)10; j++)
      if ((t * 10 + j) % b == 0) {
        p = true;
        t = t * 10 + j;
        st += "0";
        st[st.size() - 1] += j;
        break;
      }
    if (p == false) {
      cout << -1 << endl;
      return 0;
    } else
      a = t % b;
  }
  cout << st << endl;
}
