class UnionFind(): def __init__(self, n): self.n = n self.parents = [-1] * n def find(self, x): if self.parents[x] < 0: return x else: self.parents[x] = self.find(self.parents[x]) return self.parents[x] def union(self, x, y): x = self.find(x) y = self.find(y) if x == y: return if self.parents[x] > self.parents[y]: x, y = y, x self.parents[x] += self.parents[y] self.parents[y] = x def size(self, x): return -self.parents[self.find(x)] def same(self, x, y): return self.find(x) == self.find(y) def members(self, x): root = self.find(x) return [i for i in range(self.n) if self.find(i) == root] def roots(self): return [i for i, x in enumerate(self.parents) if x < 0] def group_count(self): return len(self.roots()) def all_group_members(self): return {r: self.members(r) for r in self.roots()} def __str__(self): return '\n'.join('{}: {}'.format(r, self.members(r)) for r in self.roots()) L, R = map(int, input().split()) uf = UnionFind(R - L + 1) import sys if L == 1: print(0) sys.exit() for i in range(2, R // L + 1): j = L while j * i <= R: uf.union(j-L,j*i-L) j += 1 ans = 0 print(len(uf.roots())-1)