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 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).

Sample test(s)

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<stdio.h>
#include<string.h>

int main()
{
int n, m, k;
int a[20];
scanf("%d%d", &n, &m);
a[1]=n;
a[2]=m;
scanf("%d", &k);
for(int i=3; i<=6; i++)
{
a[i]=a[i-1]-a[i-2];
}
a[0]=a[6];
printf("%d\n", (((a[k%6]%1000000007)+1000000007)%1000000007));
return 0;
}