def f(x):
  return x**3-x**2+x+1
def Is_Prime(x):
  for i in range(2,x):
    if x%i==0:
      return False
  return True
a,b = map(int,input().split())
ans = 0
for i in range(a,b+1):
  if Is_Prime(i):
    ans += f(i)
print(ans)