1 import java.io.*;
2 import java.util.*;
3 public class Main{
4 public static void main(String[] args) {
5 Scanner input = new Scanner(System.in);
6 int a, b; int n;
7 while (input.hasNext()) {
8 a = input.nextInt();
9 b = input.nextInt();
10 n = input.nextInt();
11 if (a == 0 && b == 0 && n == 0)
12 System.exit(0);
13 int f[] = new int[50];
14 for (int i = 1; i < 50; i++) {
15 if (i == 1 || i == 2) {
16 f[i] = 1;
17 }
18 else {
19 f[i] = (a * f[i - 1] + b * f[i - 2]) % 7;
20 }
21 }
22 System.out.println(f[n % 49]);
23 }
24 }
25 }