code2

/*
    HDU 1005 number sequence
*/

#include<stdio.h>
#define SEQ_LEN 100

int main(void)
{
    long n;
    int a,b,len,seq[SEQ_LEN];

    while(scanf("%d%d%ld",&a,&b,&n),a||b||n)
    {
        len=3;
        seq[1]=seq[2]=1;
        for(len=3;len<SEQ_LEN;len++)
        {
            seq[len]=(a*seq[len-1]+b*seq[len-2])%7;
            if(seq[len]==1&&seq[len-1]==1) break;
        }
        seq[0]=seq[len-2];
        printf("%d\n",seq[n%(len-2)]);
    }

    return 0;
}