Codeforces 450 B. Jzzhu and Sequences, codeforcesjzzhu

Codeforces 450 B. Jzzhu and Sequences, codeforcesjzzhu

6 loops... it is very difficult to take the modulo...

B. Jzzhu and Sequencestime limit per test1 secondmemory limit per test256 megabytesinputstandard inputoutputstandard output

Jzzhu has sorted Ted a kind of sequences, they meet the following property:

You are givenXAndY, Please calculateFNModulo 1000000007 (109 bytes + limit 7 ).

Input

The first line contains two integersXAndY(|X|, Bytes |Y| Limit ≤ limit 109). The second line contains a single integerN(1 digit ≤ DigitNLimit ≤ limit 2-109 ).

Output

Output a single integer representingFNModulo 1000000007 (109 bytes + limit 7 ).

Sample test (s) input

2 33

Output

1

Input

0 -12

Output

1000000006

Note

In the first sample,F2 bytes = bytesF1 worker + workerF3, 3 rows = second 2 rows + secondF3,F3 rows = rows 1.

In the second sample,F2 bytes = average-cost 1; average-cost 1 modulo (109 bytes + limit 7) equals (109 bytes + limit 6 ).

#include <iostream>#include <cstdio>#include <cstring>#include <algorithm>using namespace std;typedef long long int LL;const LL mod=1000000007LL;LL a,b,n;int main(){    cin>>a>>b>>n;    n--;    n=n%6;    LL ans=0;    switch(n)    {        case(0):         {            ans=(a+mod)%mod;            break;        }        case(1):        {            ans=(b+mod)%mod;            break;        }        case(2):        {            ans=(b-a+2*mod)%mod;            break;        }        case(3):        {            ans=(mod-a)%mod;            break;        }        case(4):        {            ans=(mod-b)%mod;            break;        }        case(5):        {            ans=(a-b+2*mod)%mod;            break;        }    }    cout<<ans<<endl;    return 0;}