cf450B. 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 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 -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).

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<algorithm>
#include<queue>
#include<list>
#include<cmath>
#include<vector>
#define MOD 1000000007ll
using namespace std;
const int maxn=10010;
int main()
{
long long x,y,n;
scanf("%lld%lld%lld",&x,&y,&n);
long long k=n%6;
if(k==1){
printf("%lld\n",(x+4*MOD)%MOD);
}
else if(k==2){
printf("%lld\n",(y+4*MOD)%MOD);
}
else if(k==3){
printf("%lld\n",(y-x+4*MOD)%MOD);
}
else if(k==4){
printf("%lld\n",(-x+4*MOD)%MOD);
}
else if(k==5){
printf("%lld\n",(-y+4*MOD)%MOD);
}
else if(k==0){
printf("%lld\n",(x-y+4*MOD)%MOD);
}
return 0;
}