// sarkany.cpp : This file contains the 'main' function. Program execution begins and ends there.
//

#include <iostream>
#include <cmath>
#define ll long long
using namespace std;
ll T, a, b, n;
int main()
{
    T = 3;
    while (T--)
    {
        cin >> a >> b >> n;
        ll sz = a * b;
        ll r = a % b;
        while (r)
        {
            a = b;
            b = r;
            r = a % b;
        }
        sz /= b;
        ll szj = sz,db=0;
        
        while (szj)
        {
            szj /= 10;
            db++;
        }
        if (db <= n)
        {
            cout << sz;
            for (int i = db; i < n; ++i)cout << '0';
        }
        else cout << "-1";
        cout << "\n";
    }
    return 0;
}

// Run program: Ctrl + F5 or Debug > Start Without Debugging menu
// Debug program: F5 or Debug > Start Debugging menu

// Tips for Getting Started: 
//   1. Use the Solution Explorer window to add/manage files
//   2. Use the Team Explorer window to connect to source control
//   3. Use the Output window to see build output and other messages
//   4. Use the Error List window to view errors
//   5. Go to Project > Add New Item to create new code files, or Project > Add Existing Item to add existing code files to the project
//   6. In the future, to open this project again, go to File > Open > Project and select the .sln file