Codeforces Round #257 (Div. 2 ） B. Jzzhu and Sequences

B. Jzzhu and Sequences

time limit per test

1 second

memory limit per test

256 megabytes

input

standard input

output

standard output

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 test(s)

Input

2 3
3

Output

1

Input

0 -1
2

Output

1000000006

Note

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<iostream>
#include<string.h>
#include<stdio.h>
#include<ctype.h>
#include<algorithm>
#include<stack>
#include<queue>
#include<set>
#include<math.h>
#include<vector>
#include<map>
#include<deque>
#include<list>
using namespace std;
#define M 1000000007
int main()
{
    __int64 n,a[6];
    scanf("%I64d%I64d%I64d", &a[0], &a[1], &n);
    a[0]=a[0]%M;
    a[1]=a[1]%M;
    a[2]=(a[1]-a[0])%M;
    a[3]=(-a[0])%M;
    a[4]=(-a[1])%M;
    a[5]=(a[0]-a[1])%M;
    printf("%I64d
", a[(n-1)%6]>=0? a[(n-1)%6] : a[(n-1)%6]+M);
    
    
    return 0;
}