#include <iostream>
#include <fstream>
using namespace std;
ifstream f("sum.in");
ofstream g("sum.out");
int cmmdc(int a, int b)
{
if(b)return cmmdc(b,a%b);
    else
    return a;
}
int main()
{
int a,p=0,i;
f>>a;
for(i=0;i<=2*a;i++){
        if (cmmdc(a,i)==1)p++;
}
g<<p;
return 0;
}