#include<iostream>

#include<cstdio>

#include<cstring>

#include<algorithm>

#include<cmath>

using namespace std;

int Euler(int n)

{

    int res=n;

    for(int i=2;i*i<=n;i++)

    {

        while(n%i==0)

        {

            n/=i; res-=(res/i);

            while(n%i==0)

                n/=i;

        }

    }

    if(n>1)

       res-=(res/n);

    return res;

}

int main()

{

    int p;

    while(~scanf("%d",&p))

        printf("%d\n",Euler(p-1));

    return 0;

}

#include<iostream>

#include<cstdio>

#include<cstring>

using namespace std;

typedef long long ll;

#define N 1000000

int e[N+5];

void init()

{

    int i,j;

    memset(e,0,sizeof(e));

    for(i=2;i<=N;i++)

    {

        if(!e[i])

        {

            for(j=i;j<=N;j+=i)

            {

                if(!e[j])

                    e[j]=j;

                e[j]=e[j]/i*(i-1);

            }

        }

    }

}

int main()

{

    int n;

    init();

    while(scanf("%d",&n)&&n)

    {

        ll res=0;

        for(int i=2;i<=n;i++)

            res+=e[i];

        printf("%I64d\n",res);

    }

    return 0;

}