#include<stdio.h>
int fun(int,int,int );
int main()
{
    int a,b;
    long long int n;
while(scanf("%d %d %lld",&a,&b,&n)!=EOF&&(a||b||n))
{
    int arr[50]={1,1};
    for(int i=2;i<=48;i++)
    arr[i]=(a*arr[i-1]+b*arr[i-2])%7;
    if(n%49==0) printf("%d",arr[48]);
    else
        printf("%d\n",arr[n%49-1]);
}
return 0;

}