def finalState(operations):
    if not operations:
        return 0
    
    max_index = 0
    for left, right in operations:
        max_index = max(max_index, right)
    
    states = [False] * (max_index + 1)
    toggles = [0] * (max_index + 2)  
    
    for left, right in operations:
        toggles[left] += 1
        if right + 1 <= max_index:
            toggles[right + 1] -= 1
    
    toggle_count = 0
    for i in range(max_index + 1):
        toggle_count += toggles[i]
        if toggle_count % 2 == 1:
            states[i] = not states[i]
    
    sum_indices = 0
    for i in range(max_index + 1):
        if states[i]:
            sum_indices += i
    
    return sum_indices

 def getMaxEfficiency(arrivalTime):
    arrivalTime.sort()
    n = len(arrivalTime)
    max_efficiency = float('-inf')
    
    i = 0
    for j in range(n):
        tested_cases = j - i + 1
        active_time = arrivalTime[j] - arrivalTime[i]
        efficiency = tested_cases - active_time
        
        max_efficiency = max(max_efficiency, efficiency)

        while active_time >= tested_cases:
            i += 1
            active_time = arrivalTime[j] - arrivalTime[i]
            tested_cases = j - i + 1

    return max_efficiency
 

def sum_pf(n):
    s = 0
    f = 2
    if n % f == 0:
        s += f
        while n % f == 0:
            n //= f
    for f in range(3, int(n**0.5) + 1, 2):
        if n % f == 0:
            s += f
            while n % f == 0:
                n //= f
    if n > 2:
        s += n
    return s

n = int(input())
print(sum_pf(n))