1 #include<stdio.h>
 2 #include<cmath>
 3 #include<iostream>
 4 #include<cstring>
 5 #include<algorithm>
 6 #include<queue>
 7 using namespace std;
 8 int rec[60];
 9 int main()
10 {
11     int a, b, n;
12     rec[0] = rec[1] = rec[2] = 1;
13     while( scanf( "%d %d %d", &a, &b, &n ), a | b | n )
14     {
15         int beg, end, flag = 0;
16         for( int i = 3; i <= n && !flag; ++i )
17         {
18             rec[i] = ( a * rec[i-1] + b * rec[i-2] ) % 7;
19             for( int j = 2; j <= i - 1; ++j )
20             {
21                 if( rec[i] == rec[j] && rec[i-1] == rec[j-1] )
22                 {
23                     beg = j, end = i;
24                     flag = 1;
25                     break;
26                 }
27             }
28         }
29         if( flag )
30         {
31             printf( "%d\n", rec[beg+(n-end)%(end-beg)] );
32         }
33         else
34             printf( "%d\n", rec[n] );
35     }
36     return 0;
37 }