#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, p, q;
  cin >> n >> p >> q;
  long long sum = -1;
  for (int i = 0; i < 10; i++) {
    if ((n * 10 + i) % p == 0) {
      sum = (n * 10 + i);
      break;
    }
  }
  if (sum == -1)
    cout << sum << endl;
  else {
    cout << sum;
    for (int i = 1; i < q; i++) cout << "0";
    cout << endl;
  }
}
