MOD = 10 ** 9 + 7
INF = 10 ** 20
import sys
input = sys.stdin.readline
sys.setrecursionlimit(100000000)
from collections import defaultdict
dy = (-1,0,1,0)
dx = (0,1,0,-1)

def main():
    n = int(input())
    if n == 1:
        print(1)
        return
    ans = 0
    for i in range(1,n):
        if i * i > n:
            break
        if i * i == n:
            ans += i
            break
        if n%i == 0:
            ans += i
            ans += n//i
    
    print(ans)          

if __name__ =='__main__':
    main()