#!usr/bin/env python3
from collections import defaultdict, deque
from heapq import heappush, heappop
from itertools import permutations, accumulate
import sys
import math
import bisect
def LI(): return [int(x) for x in sys.stdin.readline().split()]
def I(): return int(sys.stdin.readline())
def IR(n):
    return [I() for _ in range(n)]
def LIR(n):
    return [LI() for _ in range(n)]

sys.setrecursionlimit(1000000)
mod = 1000000007

def main():
    n = I()
    i = 2
    ans = 0
    while i*i <= n:
        while n%i == 0:
            n //= i
            ans += i
        i += 1
    ans += n if n > 1 else 0
    print(ans)
    return


if __name__ == "__main__":
    main()