Codeforces Round #383 (Div. 2) A.Arpa’s hard exam and Mehrdad’s naive cheat【循环节/快速幂】

本文链接：https://blog.youkuaiyun.com/mengxiang000000/article/details/53503168

本文介绍了一种快速计算1378^n的末位数字的方法，通过寻找循环节或使用快速幂算法解决编程竞赛中的数学问题。

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There exists an island called Arpa’s land, some beautiful girls live there, as ugly ones do.

Mehrdad wants to become minister of Arpa’s land. Arpa has prepared an exam. Exam has only one question, given n, print the last digit of 1378ⁿ.

$\text{[math]}$

Mehrdad has become quite confused and wants you to help him. Please help, although it's a naive cheat.

Input

The single line of input contains one integer n (0 ≤ n ≤ 10⁹).

Output

Print single integer — the last digit of 1378ⁿ.

Examples

Input

Output

Input

Output

Note

In the first example, last digit of 1378¹ = 1378 is 8.

In the second example, last digit of 1378² = 1378·1378 = 1898884 is 4.

题目大意：

求1378^n%10的值。

思路：

1、寻找循环节，但是别忘了n==0的情况，或者直接用快速幂的方式。

Ac代码：

#include<stdio.h>
#include<string.h>
using namespace std;
#define ll __int64
long long int kuaisumi(long long int a,long long int b,int mod)
{
    long long int tmp=a%mod;
    long long int ans=1;
    int n=b;
    while(n)
    {
        if(n%2==1)
        {
            ans=(ans*tmp)%mod;
            n-=1;
        }
        else
        {
            tmp=(tmp*tmp)%mod;
            n/=2;
        }
    }
    return ans;
}
int main()
{
    ll n;
    while(~scanf("%I64d",&n))
    {
        printf("%I64d\n",kuaisumi(1378,n,10));
    }
}