def factorization(n):
    arr = []
    temp = n
    for i in range(2, int(-(-n**0.5//1))+1):
        if temp%i==0:
            cnt=0
            while temp%i==0:
                cnt+=1
                temp //= i
            arr.append([i, cnt])

    if temp!=1:
        arr.append([temp, 1])

    if arr==[]:
        arr.append([n, 1])

    return arr

n = int(input())

lis = factorization(n)

ans = 0

if lis == [[1,1]]:
    print(0)
    exit()
    
for i,j in lis:
    ans += i*j
    
print(ans)