import time

n = int(input())
sum = 0
x = 2
st = time.time()
sn = int(n**0.5+10)

is_prime = [False, False]+[True]*(sn)
prime = []
for i in range(2,sn):
    if is_prime[i] and i*i<=n:
        prime.append(i)
        j = 2
        while i*j<=sn:
            is_prime[i*j] = False
            j+=1

for x in prime:
    y = 2
    while y*y<=x and 0<x%y:
        y+=1
    if x==y or 0<x%y:
        k = x*x
        while(k<=n):
            sum+=k
            k*=x
    x+=1

ed = time.time()

print(int(sum))