#include <iostream>
#include <utility>
using namespace std;

long gcd(long x, long y) {
    long r;
    if (y > x) swap(x, y);
    while (y > 0) {
        r = x % y;
        x = y;
        y = r;
    }
    return x;
}

int main() {
    long N;
    cin >> N;
    cout << gcd(N, (N - 1) * N / 2);
}