n = int(input())

n_s = int(n**(1/2))


A=list(range(2,n_s+1))
p=list()
while A[0]**2<=n_s:
	tmp=A[0]
	p.append(tmp)
	A=[e for e in A if e%tmp!=0]
primes=p+A

s = 0
i = 63
for p in primes:
    while p**i > n:
        i -= 1
    s += (p**(i+1)-1)/(p-1)-(1+p)

print(int(s))