#include <bits/stdc++.h>

using namespace std;
int lnko(int a, int b) {
    int m=a%b;
    while (m!=0) {
        a=b;
        b=m;
        m=a%b;
    }
    return b;
}
unsigned long long lkkt (int a, int b) {
    int t=a;
    while (t%b!=0) t=t+a;
    return t;
}
void szam (int a, int b, int n) {
    unsigned long long t=lkkt(a,b);
        if (t>=pow(10,n)) cout<<-1<<endl;
        else {
            int i=0;
            unsigned long long k=1;
            while (t/k!=0) {
                i++;
                k=k*10;
            }
            cout<<t;
            for (int j=1; j<=(n-i); j++) cout<<0;
            cout<<endl;
        }
    }

int main()
{
    //ifstream f("be.in");
    int a,b,n;
    for (int u=1; u<=3; u++) {
        //f>>a>>b>>n;
        cin>>a>>b>>n;
        szam(a,b,n);
    }
    return 0;
}