#include <bits/stdc++.h>
#include "atcoder/all"
#define debug cout << "OK" << endl;
template<typename T>
inline bool chmax(T& a, const T b) { if (a < b) { a = b; return true; } return false; }
template<typename T>
inline bool chmin(T& a, const T b) { if (a > b) { a = b; return true; } return false; }
inline int Code(char c) {
	if ('A' <= c and c <= 'Z')return (int)(c - 'A');
	if ('a' <= c and c <= 'z')return (int)(c - 'a');
	if ('0' <= c and c <= '9')return (int)(c - '0');
	assert(false);
}
using namespace std;
using namespace atcoder;
using minit = modint1000000007;
constexpr int MOD = 1000000007;
constexpr int MOD2 = 998244353;
constexpr int INF = (1LL << 63);

template<typename T>
ostream& operator << (ostream& st, const vector<T>& v) {
	for (const T value : v) {
		st << value << " ";
	}
	return st;
}
template<typename T>
istream& operator >> (istream& st, vector<T>& v) {
	for (T& value : v) {
		st >> value;
	}
	return st;
}

int pow_(const int a, const int b, const int m = INF) {
	int res = 1;
	int base = a;
	for (int i = 0; i < 64; i++) {
		if (b & (1ll << i))res *= base;
		res %= m;
		base = base * base;
		base %= m;
	}
	return res;
}
inline int gcd(const int a, const int b) { return (b == 0 ? a : gcd(b, a % b)); }
inline int lcm(const int a, const int b) { return a * b / gcd(a, b); }
//
class nCk {
public:
	const int m;
	const int MAXIMUM = 1000000;
	vector<int> fac, facinv, inv;
	nCk(int m_);
	~nCk();
	int com(int n, int k)const;
};
nCk::nCk(int m_):m(m_) {
	fac.resize(MAXIMUM + 3);
	facinv.resize(MAXIMUM + 3);
	inv.resize(MAXIMUM + 3);
	fac[0] = fac[1] = 1;
	facinv[0] = facinv[1] = 1;
	inv[1] = 1;
	for (int i = 2; i < MAXIMUM + 2; i++) {
		fac[i] = fac[i - 1] * i % m;
		inv[i] = m - inv[m % i] * (m / i) % m;
		facinv[i] = facinv[i - 1] * inv[i] % m;
	}
}
nCk::~nCk(){}
int nCk::com(int n, int k)const {
	if (n < k)return 0;
	assert(!(n < 0 || k < 0));
	return fac[n] * (facinv[k] * facinv[n - k] % m) % m;
}
template<typename T>
vector<long long> press(const vector<T>& arr) {
	vector<T> X = arr;
	sort(X.begin(), X.end());
	X.erase(unique(X.begin(), X.end()), X.end());
	vector<long long> ans(arr.size());
	for (int i = 0; i < arr.size(); i++) {
		ans[i] = lower_bound(X.begin(), X.end(), arr[i]) - X.begin();
	}
	return ans;
}
class LCA {
public:
	vector<vector<long long>> parent;
	vector<long long> dist;
	vector<vector<long long>> G;
	LCA(const vector<vector<long long>>& gr) { init(gr); }
	void dfs(long long v, long long p, long long d) {
		parent[0][v] = p;
		dist[v] = d;
		for (long long next : G[v]) {
			if (next == p)continue;
			dfs(next, v, d + 1);
		}
		return;
	}
	void init(const vector<vector<long long>>& gr) {
		G = gr;
		parent.assign(33, vector<long long>(G.size(), -1LL));
		dist.assign(G.size(), -1LL);
		dfs(0LL, -1LL, 0LL);
		for (int i = 0; i < 32; i++) {
			for (int j = 0; j < G.size(); j++) {
				if (parent[i][j] < 0LL) {
					parent[i + 1][j] = -1LL;
				}
				else {
					parent[i + 1][j] = parent[i][parent[i][j]];
				}
			}
		}
		return;
	}
	long long lca(long long u, long long v) {
		if (u == -1 and v == -1)return -1;
		else if (u == -1)return v;
		else if (v == -1)return u;
		if (dist[u] < dist[v])swap(u, v);
		long long between = dist[u] - dist[v];
		for (int i = 0; i < 33; i++) {
			if (between & (1LL << i)) { u = parent[i][u]; }
		}
		if (u == v)return u;
		for (int i = 32; i >= 0; i--) {
			if (parent[i][u] != parent[i][v]) {
				u = parent[i][u];
				v = parent[i][v];
			}
		}
		assert(parent[0][u] == parent[0][v]);
		return parent[0][u];
	}
	long long get_dist(long long u, long long v) {
		return dist[u] + dist[v] - 2 * dist[lca(u, v)];
	}
	bool on_path(long long u, long long v, long long a) {
		return get_dist(u, v) == get_dist(u, a) + get_dist(v, a);
	}
};
//

class Solver {
public:
	int T;
	Solver() :T(1) {}
	~Solver(){}
	void ios()const;
	void multi();
	void solve() const;
	void sp(int x)const;
	void ft()const;

	//
	
	//
};
void Solver::ios() const {
	cin.tie(nullptr);
	ios_base::sync_with_stdio(false);
	return;
}
void Solver::multi() {
	cin >> T;
	return;
}
void Solver::sp(const int x)const {
	cout << fixed << setprecision(x) << endl;
	return;
}

void Solver::ft() const {
	
}
void Solver::solve() const {
	int L, R;
	cin >> L >> R;
	dsu d(R + 1);
	int cnt = 0;
	for (int e = L; e <= R; e++) {
		for (int f = e * 2; f <= R; f += e) {
			if (!d.same(e, f)) {
				d.merge(e, f);
				cnt++;
			}
		}
	}
	cout << (R - L - cnt) << endl;
}

signed main() {
	Solver solver;
	solver.ios();
	//solver.ft();
	//solver.multi();
	//solver.sp();
	for (int i = 0; i < solver.T; i++)
		solver.solve();
	return 0;
}

/*
* わらびのコードこーどすぺーす
 (σ･∀･)σｹﾞｯﾂ!!
*/