#include <iostream>

using namespace std;

int main()
{
    for (int q=0; q<3; q++)
    {
        unsigned long long int A, B, N;
        cin >> A >> B >> N;
        unsigned long long int lnko, lkkt, AB;
        AB=A*B;
        while (A!=B)
        {
            if (A>B)
            {
                A=A-B;
            }
            else
            {
                B=B-A;
            }
        }
        lnko=A;
        lkkt=AB/lnko;

        string s;
        s=to_string(lkkt);
        if (s.size()>N)
        {
            cout << -1 << endl;
        }
        else if (s.size()==N)
        {
            cout << lkkt << endl;
        }
        else
        {
            cout << lkkt;
            for (unsigned long long int i=2; i<=N-s.size(); i++)
            {
                cout << 0;
            }
            cout << 0 << endl;
        }
    }

    return 0;
}