poj_2480

#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <set>
#include <queue>
#include <map>
using namespace std;
#define MAX(x,y) (((x)>(y))?(x):(y))
#define MIN(x,y) (((x)<(y))?(x):(y))
#define N 500010
#define pi acos(-1.0)
#define inf 100000000
typedef long long ll;
typedef unsigned long long ull;
int main(){
    //freopen("in.txt","r",stdin);
    ll n;
    while(~scanf("%lld",&n)){
        ll ans=n;
        for(ll i=2;i*i<=n;i++){
            if(n%i==0){
                ll a=0;
                while(n%i==0){
                    a++;
                    n/=i;
                }
                ans=ans+ans*a*(i-1)/i;
            }
        }
        if (n!=1) {
            ans = ans + ans*(n-1)/n;
      }
        printf("%lld\n",ans);
    }
    return 0;
}

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