Jzzhu and Sequences CodeForces

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).

Example

Input

2 33

Output

1

Input

0 -12

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).

题意：给你f[1],f[2]的值，然后求任意一项的值，，，

思路：写几组数据就看出来，序列是以6个为循环，值分别为 f[1],f[2],f[3].-f[1],-f[2],-f[3].......取余求值即可》》》》》》》。

下面附上代码：

#include<bits/stdc++.h>using namespace std;typedef long long ll;const ll mod=1000000007;ll f[7];int main(){ll x,y,n;scanf("%lld %lld",&x,&y);f[1]=x,f[2]=y,f[3]=f[2]-f[1];scanf("%lld",&n);for(int i=4;i<=6;i++)f[i]=-f[i-3];f[0]=f[6];ll p=f[n%6];printf("%lld\n",(p%mod+mod)%mod);return 0;}