//第一版，直接暴力递归，超时
#include<iostream>
using namespace std;
long long int fac(int A, int B, int n)
{
    if (n == 1 || n == 2)
        return 1;
    else
        return (A * fac(A,B,n - 1) + B * fac(A,B,n - 2)) % 7;
}
int main()
{
    int A, B, n;
    while (cin >> A >> B >> n&&A != 0 && B != 0 && n != 0)
    {
        cout << fac(A, B, n % 48) << endl;
    }
    return 0;
}