CodeForces 450B

Description

Jzzhu has invented a kind of sequences, they meet the following property:

You are given x and y, please calculate f_n modulo 1000000007(10⁹ + 7).

Input

The first line contains two integers x and y(|x|, |y| ≤ 10⁹). The second line contains a single integer n(1 ≤ n ≤ 2·10⁹).

Output

Output a single integer representing f_n modulo 1000000007(10⁹ + 7).

Sample Input

Input

2 3
3

Output

1

Input

0 -1
2

Output

1000000006

Hint

In the first sample, f₂ = f₁ + f₃, 3 = 2 + f₃, f₃ = 1.

In the second sample, f₂ =  - 1;  - 1 modulo (10⁹ + 7) equals (10⁹ + 6).

#include<cstdio>
#include<cstring>
#include<iostream>
#include<cstdlib>
#include<algorithm>

using namespace std;

int a[10],b,sum;
int main()
{
    int n,y,x;
    while(~scanf("%d%d",&x,&y))
    {
        scanf("%d",&n);
        x=(x+1000000007)%1000000007;
        y=(y+1000000007)%1000000007;
        a[0]=x;
        a[1]=y;
        for(int i=2; i<=10; i++)
        {
            a[i]=(a[i-1]-a[i-2])%1000000007;
            a[i]=(a[i]+1000000007)%1000000007;
        }
        printf("%d\n",a[(n-1)%6]%1000000007);
    }
}