Jzzhu has invented a kind of sequences, they meet the following property:
You are given x and y, please calculate fn 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 fn modulo 1000000007 (109 + 7).
Examples
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).
题解:分析可以知道,f(x)=f(x+6);注意结果不能为负数;
代码:
#include <iostream>
using namespace std;
int main()
{
int x,y,n;
int a[10];
cin>>x>>y;
cin>>n;
a[1]=x;
a[2]=y;
for(int i=3;i<=6;i++)
a[i]=a[i-1]-a[i-2];
a[0]=a[6];
cout<<(((a[n%6]%1000000007)+1000000007)%1000000007)<<endl;
return 0;
}