HDU1005

#include<iostream>
#include<algorithm>
#include<string>
#include<cstring>
#include<cmath>
#include<iomanip>
using namespace std;
int m[50];
int main()
{
	
	int a,b,n;
	m[1]=1;
	m[2]=1;
	while(cin>>a>>b>>n)
	{
		if(a==0&&b==0&&n==0) break;
		for(int i=3;i<50;i++)
		{
			m[i]=(a*m[i-1]+b*m[i-2])%7;
		}
		
		n=n%49;
		cout<<m[n]<<endl;
	}
	return 0;
}