#include <iostream>
#include <fstream>
#include <cstring>
#include <vector>
#include <algorithm>
using namespace std;
ifstream fin("date.in");
ofstream fout("date.out");
//#define cout fout

bool prim(int n)
{
    if(n <= 1)
        return 0;
    if(n == 2)
        return 1;
    if(n % 2 == 0)
        return 0;
    for(int i = 3 ; i * i <= n ; i += 2)
    {
        if(n % i == 0)
            return 0;
    }
    return 1;
}

int main()
{
    int n, rez, i;
    cin >> n;
    if(n <= 100)
    {
        rez = 1;
        for(i = 1 ; i < n ; i++)
        {
            rez = (rez * i) % n;
        }
        cout << rez << "\n";
    }
    else
    {
        if(prim(n))
            cout << n - 1 << "\n";
        else
            cout << 0 << "\n";
    }
}