#include <cstdio>
#include <iostream>
#include <cstdlib>
#include <algorithm>
#define ll long long
using namespace std;
ll prime[99999],cnt;
ll gcd(ll a,ll b)
{
if(!b) return a;
return gcd(b,a%b);
}
ll mul(ll x,ll y,ll mod)//¿ìËÙ¼Ó
{
ll ans=0;
while(y)
{
if(y%(1ll*2)) ans=(ans+x%mod)%mod;
y/=(1ll*2);
x=(x%mod+x%mod)%mod;
}
return ans;
}
ll fast_pow(ll x,ll y,ll m)//¿ìËÙÃÝ
{
ll ans=1;
x%=m;
while(y)
{
if(y%2)
ans=mul(ans, x, m);
y/=2;
x=mul(x, x, m);
}
return ans;
}
bool MR(ll n)
{
if(n == 2) return 1;
if(n < 2 || !(n & 1)) return 0;
ll m=n-1;
ll k=0;
while((k&1)==0)
{
k++;
m/=2;
}
for(int i=0; i<12; i++)
{
ll a=rand()%(n - 1)+1;
ll x=fast_pow(a, m, n);
ll y=0;
for(int j=0; j<k; j++)
{
y=mul(x,x,n);
if(y==1&&x!=1&&x!=n-1) return 0;
x = y;
}
if(y!=1) return 0;
}
return 1;
}
ll rho(ll n,ll c)//ÕÒÒò×Ó
{
ll i=1,k=2;
ll x=rand()%(n-1)+1;
ll y=x;
while(1)
{
i++;
x=(mul(x,x,n)+c)%n;
ll d=gcd(((y-x)+n)%n,n)%n;
if(d>1&&d<n) return d;
if(y==x) return n;
if(i==k)//Ò»¸öÓÅ»¯£¬ÎÒTMÒ²²»ÖªµÀΪɶ
{
y=x;
k<<=1;
}
}
}
void find(ll n,ll c)//·Ö½âµÄµÝ¹é¹ý³Ì
{
if(n==1) return;
if(MR(n))
{
prime[++cnt]=n;
return;
}
ll p=n;
ll k=c;
while(p>=n) p=rho(n,c--);
find(n/p,c);
find(p,c);
}
int main()
{
ll n;
scanf("%lld",&n);
find(n,120);
sort(prime+1,prime+cnt+1);
ll t=unique(prime+1,prime+cnt+1)-prime-1;//È¥Öغ¯Êý£¬²»ÒªÍüÁËÈ¥ÁËÖظ´µÄÖÊÊý°¡
/* for(int i=1;i<=t;i++)
printf("%lld ",prime[i]);*/
double ans=n;
for(int i=1;i<=t;i++)
ans*=(1.0-(1.0/(double)prime[i]));
printf("%lld",(ll) ans);
}
ll powmod(ll a,ll b) {ll res=1;a%=mod; assert(b>=0);
for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;}
ll gcd(ll a,ll b) { return b?gcd(b,a%b):a;}
