N！Again

N！Again

 

WhereIsHeroFrom:             Zty, what are you doing ? 
Zty:                                     I want to calculate N!...... 
WhereIsHeroFrom:             So easy! How big N is ? 
Zty:                                    1 <=N <=1000000000000000000000000000000000000000000000… 
WhereIsHeroFrom:             Oh! You must be crazy! Are you Fa Shao? 
Zty:                                     No. I haven's finished my saying. I just said I want to calculate N! mod 2009 


Hint : 0! = 1, N! = N*(N-1)! 

Input

Each line will contain one integer N(0 <= N<=10^9). Process to end of file. 

Output

For each case, output N! mod 2009 

Sample Input

4 
5

Sample Output

24
120

大体题意为n的阶乘与2009取模，其实从41开始结果为0，代码如下：

#include <iostream>
#include <cstdio>
using namespace std;
int main()
{
    long long int i;
    long long int a;
    while(scanf("%lld", &a) != EOF)
    {
        if(a > 40)
        {
            cout << 0 << endl;
            continue;
        }
        long long int ans = 1;
        for(i = 0; i < a; i++)
        {
            ans = (ans % 2009) * ((i + 1) % 2009) % 2009;
        }
        cout << ans << endl;
    }
    return 0;
}