davidwang's Blog

这道题进去看status发现代码好短，肯定有什么规律，就把后面那部分打个表一看发现就是n*m然后就交了一发Wa了……以为结论是错的后来去找题解发现是对的，就是有个地方忘记mod了

至于证明吗看PoPoQQQ大神的题解吧： http://blog.csdn.net/PoPoQQQ/article/details/46820313

//coder : davidwang
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <climits>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <bitset>
#include <deque>
#include <iostream>
using namespace std;
#define LL long long
#define X first
#define Y second
template<typename T>
inline T sqr(const T &x){ return x*x; }
inline int read()
{
	int ret=0,f=1; char ch;
	for (ch=getchar();ch<'0' || ch>'9';ch=getchar())
		if (ch=='-') f=-f;
	for (;'0'<=ch && ch<='9';ch=getchar())
		ret=ret*10+ch-'0';
	return ret*f;
};
const int  mod = 998244353;
inline LL phi(LL x){
	LL i,ret=x;
	for (i=2;i*i<=x;i++){
		if (x%i==0){
			ret=ret/i*(i-1);
			while (x%i==0) x/=i;
		}
	}
	if (x!=1) ret=ret/x*(x-1);
	return ret;
}
int main()
{
#ifndef ONLINE_JUDGE
	freopen("a.in","r",stdin);
	freopen("a.out","w",stdout);
#endif
	LL n,m;
	cin>>n>>m;
	LL a=phi(n)%mod,b=phi(m)%mod;
	n%=mod; m%=mod;
	a=a*b%mod;
	a=a*n%mod;
	a=a*m%mod;
	cout<<a<<endl;
	return 0;
}