import sys
input = sys.stdin.readline

import math

def facts(x):
    xr=math.ceil(math.sqrt(x))

    LIST=[]
    for i in range(1,xr+1):
        if x%i==0:
            LIST.append(i)
            LIST.append(x//i)
    return sorted(set(LIST))


L,R=map(int,input().split())

# UnionFind

Group = [i for i in range(2*10**5+1)] # グループ分け
Nodes = [1]*(2*10**5+1) # 各グループのノードの数

def find(x):
    while Group[x] != x:
        x=Group[x]
    return x

def Union(x,y):
    if find(x) != find(y):
        if Nodes[find(x)] < Nodes[find(y)]:
            
            Nodes[find(y)] += Nodes[find(x)]
            Nodes[find(x)] = 0
            Group[find(x)] = find(y)
            
        else:
            Nodes[find(x)] += Nodes[find(y)]
            Nodes[find(y)] = 0
            Group[find(y)] = find(x)

for i in range(L):
    Union(i,0)
for i in range(R+1,2*10**5+1):
    Union(i,0)

for i in range(R,L-1,-1):
    LIST=[j for j in facts(i) if j>=L]
    for j in LIST:
        Union(i,j)
    
print(len(set([find(i) for i in range(2*10**5+1)]))-2)