#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <cmath>
#include <vector>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <queue>
#include <ctime>
#include <cassert>
#include <complex>
#include <string>
#include <cstring>
#include <chrono>
#include <random>
#include <queue>
#include <bitset>
#include <stack>
#include <functional>

#ifdef LOCAL
    #define eprintf(...) fprintf(stderr, __VA_ARGS__)
#else
    #define eprintf(...) 42
#endif

#define rep_(i, a_, b_, a, b, ...) for (int i = (a), i##_len = (b); i < i##_len; ++i)
#define rep(i, ...) rep_(i, __VA_ARGS__, __VA_ARGS__, 0, __VA_ARGS__)
#define reprev_(i, a_, b_, a, b, ...) for (int i = (b-1), i##_min = (a); i >= i##_min; --i)
#define reprev(i, ...) reprev_(i, __VA_ARGS__, __VA_ARGS__, 0, __VA_ARGS__)
#define all(x) (x).begin(), (x).end()
template <class T> bool chmax(T &a, const T &b) { if (a < b) { a = b; return 1; } return 0; }
template <class T> bool chmin(T &a, const T &b) { if (b < a) { a = b; return 1; } return 0; }
// template <class T> T gcd(T a, T b) { return b ? gcd(b, a % b) : a; }
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair <int,int> P;
typedef long double ld;

struct UnionFind {
    vector< int > data;
    UnionFind(int sz) {
        data.assign(sz, -1);
    }
    bool unite(int x, int y) {
        x = find(x), y = find(y);
        if(x == y) return (false);
        if(data[x] > data[y]) swap(x, y);
        data[x] += data[y];
        data[y] = x;
        return (true);
    }
    int find(int k) {
        if(data[k] < 0) return (k);
        return (data[k] = find(data[k]));
    }    
    int size(int k) {
        return (-data[find(k)]);
    }
};

int main (void)
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    int l, r; cin >> l >> r;
    UnionFind uf(r - l + 1);
    rep (i, l, r) {
        for (int j = 2; j * i <= r; j++) {
            uf.unite(i - l, i * j - l);
        }
    }
    set<int> st;
    rep (i, l, r + 1) st.insert(uf.find(i - l)); 
    cout << st.size() - 1 << "\n";
    return 0;
}