N=int(input())
v=[0]*(10**6)
for x in range(2,10**6):
  if v[x]==1:
    continue
  for y in range(2,10**6):
    if x*y>=10**6:
      break
    v[x*y]=1
p=[]
for x in range(2,10**6):
  if v[x]==0:
    p.append(x)
result=0
for x in p:
  for n in range(2,100):
    y=x**n
    if y>N:
      break
    result+=y
print(result)