def main():
    import sys
    from math import sqrt
    input = sys.stdin.readline

    N = int(input())
    div = []
    for i in range(1, int(sqrt(N))+1):
        if N%i == 0:
            div.append(i)
            div.append(N//i)
    if div[-1] ** 2 == N:
        div.pop()
    print(sum(div))


if __name__ == '__main__':
    main()