#include<iostream>
#include<string>
#include<cstdio>
#include<vector>
#include<cmath>
#include<algorithm>
#include<functional>
#include<iomanip>
#include<queue>
#include<ciso646>
#include<utility>
#include<map>
#include<set>
#include<bitset>
#include<stack>
#include<cassert>
#include<random>
#include<unordered_map>
#include<numeric>
using namespace std;

#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define all(v) (v).begin(),(v).end()
#define stop char nyaa;cin>>nyaa;


using P = pair<int, int>;
using ll = long long;
using LP = pair<ll, ll>;

const ll inf = 1000000007;
const ll INF = inf * inf;




vector<int> G[1 << 18];
bool used[1 << 18];

void solve() {
	int l, r; cin >> l >> r;
	for (int i = l; i <= r; i++) {
		for (int j = 2 * i; j <= r; j += i) {
			G[i].push_back(j);
			G[j].push_back(i);
		}
	}
	int cnt = 0;
	for (int i = l; i <= r; i++) {
		if (used[i])continue;
		queue<int> q;
		used[i] = true; q.push(i);
		while (!q.empty()) {
			int v = q.front(); q.pop();
			for (int to : G[v]) {
				if (used[to])continue;
				used[to] = true;
				q.push(to);
			}
		}
		cnt++;
	}

	int ans = cnt - 1;
	cout << ans << "\n";
}


signed main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	//int t; cin >> t;rep(i, t)solve();
	solve();
	stop
	return 0;
}