import sys


def input(): return sys.stdin.readline().rstrip('\n')


def main():
    n = int(input())
    i = 1
    ans = 0
    while i*i <= n:
        if n % i == 0:
            ans += i
            if i != n // i:
                ans += n//i
        i += 1
    print(ans)


if __name__ == '__main__':
    main()