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

#include <iostream>
#include <numeric>
using namespace std;
int size(long long x)
{
	int s = 0;
	while (x > 0)
	{
		x = x / 10;
		s++;
	}
	return s;
}
int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	for (int i = 1; i <= 3; i++)
	{
		long long a, b, n;
		cin >> a >> b>>n;
		long long lkkt = (a * b) / gcd(a, b);
		if (size(lkkt) > n)
			cout << -1;
		else
		{
			cout << lkkt;
			for (int j = 0; j <= (size(lkkt) - n); j++)
				cout << 0;
		}
		cout << endl;
	}
}

// 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