不懂 来问问！！！

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Time limit: 1 Seconds Memory limit: 32768K
Total Submit: 4488 Accepted Submit: 988

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A number sequence is defined as follows:

f(1) = 1, f(2) = 1, f(n) = (A * f(n - 1) + B * f(n - 2)) mod 7.

Given A, B, and n, you are to calculate the value of f(n).

Input

The input consists of multiple test cases. Each test case contains 3 integers A, B and n on a single line (1 <= A, B <= 1000, 1 <= n <= 100,000,000). Three zeros signal the end of input and this test case is not to be processed.

Output

For each test case, print the value of f(n) on a single line.

Sample Input

1 1 3
1 2 10
0 0 0

Sample Output

2
5

我的程序：
#include<stdio.h>
int b;
int a;

main()
{ int f(int n);
int n;
while( scanf("%d%d%d",&a,&b,&n)!=EOF )
{ if (a!=0||b!=0||n!=0) printf("%d\n",f(n)); }
}
int f (int n)
{

if (n<=3) return 1;

return ((a*f(n-1)+b*f(n-2))%7);
}
高人来看看~~~~~~~~~```