Uva 10299 - Relatives

 // Verdict :: Accepted
// Time :: 0.119
#include <iostream>
#include <cstdio>
#include <cstring>
#include <map>
#include <string>
#include <vector>
#include <cmath>
#include <cctype>
#include <sstream>
#include <set>
#include <list>
#include <stack>
#include <queue>
#include <algorithm>
#define sf scanf
#define pf printf
#define sfint scanf ("%d %d",&a,&b)
#define sfl scanf ("%ld %ld",&a,&b)
#define sfll scanf ("%lld %lld",&a,&b)
#define sfd scanf ("%lf %lf",&a,&b)
#define sff scanf ("%f %f",&a,&b)
#define lp1(i,n) for(i=0;i<n;i++)
#define lp2(i,n) for(i=1;i<=n;i++)
#define LL long long
#define L long
#define mem(c,v) memset(c,v,sizeof(c))
#define ui unsigned int
#define ull unsigned long long int
#define nl puts("")
#define sq(x) ((x)*(x))
#define MX 1000005
#define N 100
#define MOD 10000000007
#define pb push_back
#define pi acos(-1.0)
#define sz size()
#define gc getchar ()
#define ps push
#define clr clear
#define inf 2147483647
#define bn begin()
#define ed end()

using namespace std;

LL prime[MX+15],p[MX+15],plen=0;

LL setbit(LL n, LL pos)
{
    n=n|(1<<pos);
    return n;
}

LL checkbit(LL n, LL pos)
{
    n=n&(1<<pos);
    return n;
}

void seieve(LL n)
{
    LL i,j,x=sqrt(n);

    prime[0]=setbit(prime[0],0);
    prime[0]=setbit(prime[0],1);

    for(i=4;i<=n;i+=2)
    {
        prime[i>>5]=setbit(prime[i>>5],i&31);
    }

    for(i=3;i<=x;i+=2)
    {
        if(!checkbit(prime[i>>5],i&31))
        {
            for(j=i*i;j<=n;j+=i)
            {
                prime[j>>5]=setbit(prime[j>>5],j&31);
            }
        }
    }

    for(i=1;i<=n;i++)
    {
        if(!checkbit(prime[i>>5],i&31))
        {
            p[plen++]=i;
        }
    }
}

LL divisors(LL n)
{
    LL i,j,phi=n;

    for(i=0; i<=plen and sq(p[i]) <= n ; i++)
    {
        if(!(n%p[i]))
        {
            phi-=phi/p[i];

            while(!(n%p[i]))
            {
                n/=p[i];
                if(n==0 or n==1) break;
            }
        }
    }

    if(n>1)
    {
        phi-=phi/n;
    }

    //pf("%lld",phi);
    return phi;
}

int main()
{
    seieve(MX);
    //for(LL i=0;i<plen;i++) cout << p[i] << " ";
    //divisors();
    LL n;
    while(sf("%lld",&n)==1 and n)
    {
        if(n==1)
        {
            pf("0\n");
            continue;
        }

        LL res=divisors(n);

        if(res<=0)
        {
            pf("%lld\n",n);
        }

        else
        {
            pf("%lld\n",res);
        }
    }

    return 0;
}