华华给月月出题

#include <bits/stdc++.h>
using namespace std;
#define re register
#define ll long long
const int mod=1e9+7;
const int maxn=1.3*10000000;
void read(int &a)
{
    a=0;
    int d=1;
    char ch;
    while(ch=getchar(),ch>‘9‘||ch<‘0‘)
        if(ch==‘-‘)
            d=-1;
    a=ch-‘0‘;
    while(ch=getchar(),ch>=‘0‘&&ch<=‘9‘)
        a=a*10+ch-‘0‘;
    a*=d;
}
void write(int x)
{
    if(x<0)
        putchar(45),x=-x;
    if(x>9)
        write(x/10);
    putchar(x%10+‘0‘);
}
int vis[maxn],p[maxn];
int quickmod(int x,int y)
{
    int result=1;
    int base=x;
    while(y)
    {
        if(y&1)
            result=1ll*result*base%mod;
        base=1ll*base*base%mod;
        y>>=1;
    }
    return result;
}
int main()
{
    int n;
    read(n);
    int ans=1,cnt=1;
    for(re int i=2;i<=n;i++)
    {
        if(!vis[i])
            p[cnt++]=i,vis[i]=quickmod(i,n);
        for(re int j=1;j<=cnt&&p[j]*i<=n;j++)
        {
            vis[i*p[j]]=1ll*vis[i]*vis[p[j]]%mod;
            if(i%p[j]==0)
                break;
        }
        ans^=vis[i];
    }
    write(ans);
    return 0;
}