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

#include <iostream>

int a, b, h;
using namespace std;
long long lnko(long long a,long long b) {
	long long r = a%b;
	while (r!=0) {
		a = b;
		b = r;
		r = a % b;
	}
	return a;
}

long long lkkt(long long a,long long b) {
	return a * b / lnko(a, b);
}
void sarkany() {
	cin >> a >> b >> h;
	a = lkkt(a, b);
	b = a;
	int i = 0;
	while (b!=0) {
		++i;
		b /= 10;
	}
	if (i > h) cout << -1;
	else {
		cout << a;
		while (i < h) {
			cout << 0;
			++i;
		}
	}
	cout << "\n";
}

int main() {
	for (int i = 1; i <= 3; ++i) {
		sarkany();
	}
}

// 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