参考博客:
https://blog.csdn.net/qq_33199236/article/details/52832706
https://blog.csdn.net/meituanwaimai/article/details/79090140
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<iostream>
using namespace std;
typedef long long ll;
ll n,m,p[100],cnt,sum,a[100];
//计算因子
void fac()
{
cnt=0;
ll m1=m;
for(ll i=2;i*i<=m;i++){
if(m1%i==0)
p[cnt++]=i;
while(m1%i==0)
m1/=i;
}
if(m1>1)
p[cnt++]=m1;
}
ll quick(ll a,ll b)
{
ll res=1;
while(b){
if(b&1)
res*=a;
a*=a;
b>>=1;
}
return res;
}
//容斥定理计算跟他互质的数的个数。
void dfs(int now,int step,int stop)
{
if(step==stop){
ll mm=m;
for(int i=0;i<step;i++){
mm/=a[i];
}
sum+=quick(mm,n);
return;
}
for(int i=now;i<cnt;i++){
a[step]=p[i];
dfs(i+1,step+1,stop);
}
return ;
}
int main()
{
while(~scanf("%lld%lld",&n,&m)){
fac();
ll res=quick(m,n),ans=0;
for(int i=1;i<=cnt;i++){
sum=0;
dfs(0,0,i);
if(i&1)
ans+=sum;
else
ans-=sum;
// cout<<sum<<endl;
}
printf("%lld\n",res-ans);
}
}