标签：欧拉函数，数学，数论
Description
Input
输入文件的第一行输入两个正整数 。
Output
如题
Sample Input
5 6
Sample Output
240
HINT
N,M<=10^15
直接放PoPoQ大爷的式子
http://blog.csdn.net/popoqqq/article/details/46820313
code
#include<cstdio>
#include<iostream>
#include<cstring>
#include<cstdlib>
#include<cmath>
#include<algorithm>
#define rep(i,a,b) for(LL i=a;i<=b;i++)
#define dep(i,a,b) for(LL i=a;i>=b;i--)
#define LL long long
#define mem(x,num) memset(x,num,sizeof x)
using namespace std;
const LL mod=998244353;
LL n,m;
LL phi(LL n)
{
LL t=n;
rep(i,2,sqrt(n))
if(n%i==0){
t=t/i*(i-1);
while(n%i==0)n/=i;
}
if(n!=1)t=t/n*(n-1);
return t;
}
int main()
{
cin>>n>>m;
cout<<(phi(n)%mod)*(phi(m)%mod)%mod*(n%mod)%mod*(m%mod)%mod<<endl;
return 0;
}
