#include <cstdio>
#include <cmath>

long long n, ans;
int lmt;

int phi(int x) {
	int rt = x;
	for (int i = 2; i * i <= x; ++i) {
		if (x % i == 0) {
			rt = rt / i * (i - 1);
			x /= i;
			while (x % i == 0) {
				x /= i;
			}
		}
	}
	if (x > 1) {
		rt = rt / x * (x - 1);
	}
	return rt;
}

int main(void) {
	scanf("%lld", &n);
	lmt = (int)sqrt((float)n + 0.5f);
	for (int i = 1; i <= lmt; ++i) {
		if (n % i == 0) {
			ans += (long long)i * (long long)phi(n / i);
			if (n / i != i) {
				ans += (long long)(n / i) * (long long)phi(i);
			}
		}
	}
	printf("%lld\n", ans);
	return 0;
}