Problem: Let's consider some integer X. We will call the following sequence S a sequence generated by X:
for i = 1: S[i] = X 
for i > 1: S[i] equals to the minimal positive integer such that S[i] is not a divisor of S[i - 1]. If there is no such integer than S[i - 1] is the last element of S.

For example S = (10, 3, 2) is a sequence generated by 10.

Can you find the total sum of lengths of the sequnces generated by all the integers from A  to B inclusive.

Input
The only line contains two integers: A and B. (A ≤ B)

Output 
Output the only integer - answer to the question. It's guaranteed that this value can be stored in 64-bit integer.

Constraints 
1 < A ≤ B ≤ 10^17

SAMPLE INPUT
2 6

SAMPLE OUTPUT
12

Solution (in PYTHON):

Solution:
def gcd(a,b):
   if b==0:return a
   return gcd(b,a%b)
def lcm(a,b):return a*(b/gcd(a,b))

f=[1,1,1]
for i in range(3,100):
   for j in range(1,i+1):
      if i%j!=0: 
         f.append(1+f[j])
         break

def solve(x):
   if x==0:return 0
   global f
   m=1
   ans=1   
   for v in range(2,min(x+1,50)):
      #v<m*d<=x
      inc=x/m-v/m
      m=lcm(m,v)
      inc-=x/m-v/m
      ans+=inc*(1+f[v])
   if 2<=x:ans+=1
   return ans

a,b=[int(x) for x in raw_input().split()]
print solve(b)-solve(a-1)