bzoj4173 -- 欧拉函数

 题解：http://blog.csdn.net/PoPoQQQ/article/details/46820313

 

代码：

 1 #include<iostream> 2 #include<cstdio> 3 #include<cstring> 4 #include<algorithm> 5 #include<cmath> 6 using namespace std; 7 #define M 998244353 8 #define ll long long 9 ll n,m;10 inline ll Phi(ll x){11     ll Ans=x;12     for(ll i=2;i*i<=x;i++)13     if(x%i==0){14         Ans/=i;Ans*=i-1;15         x/=i;16         while(x%i==0)x/=i;17     }18     if(x!=1)Ans/=x,Ans*=(x-1);19     return Ans%M;20 }21 int main(){22     scanf("%lld%lld",&n,&m);23     printf("%lld\n",Phi(n)*Phi(m)%M*(n%M)%M*(m%M)%M);24     return 0;25 }

bzoj4173