import java.io.*;
import java.util.*;
import java.util.stream.*;

public class Main {
    static ArrayList<Integer> primes = new ArrayList<>();
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        long left = sc.nextLong();
        long right = sc.nextLong();
        boolean[] isNotPrimes = new boolean[1000001];
        for (int i = 2; i < isNotPrimes.length; i++) {
            if (!isNotPrimes[i]) {
                primes.add(i);
                for (int j = 2; j * i < isNotPrimes.length; j++) {
                    isNotPrimes[j * i] = true;
                }
            }
        }
        int ans = 0;
        for (long i = left; i <= right; i++) {
            if (isFree(i)) {
                ans++;
            }
        }
        System.out.println(ans);
    }
    
    static boolean isFree(long x) {
        long y = x;
        for (int z : primes) {
            if (z > Math.sqrt(y)) {
                break;
            }
            int count = 0;
            while (y % z == 0) {
                count++;
                y /= z;
            }
            if (count >= 2) {
                return false;
            }
        }
        if (x != y) {
            return true;
        }
        long left = 1;
        long right = Long.MAX_VALUE / 2;
        while (right - left > 1) {
            long m = (left + right) / 2;
            if (m * m <= x) {
                left = m;
            } else {
                right = m;
            }
        }
        if (left > 1 && left * left == x) {
            return false;
        } else {
            return true;
        }
    }
}
class Utilities {
    static String arrayToLineString(Object[] arr) {
        return Arrays.stream(arr).map(x -> x.toString()).collect(Collectors.joining("\n"));
    }
    
    static String arrayToLineString(int[] arr) {
        return String.join("\n", Arrays.stream(arr).mapToObj(String::valueOf).toArray(String[]::new));
    }
}
class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    StringBuilder sb = new StringBuilder();
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public int[] nextIntArray() throws Exception {
        return Stream.of(br.readLine().split(" ")).mapToInt(Integer::parseInt).toArray();
    }
    
    public String next() throws Exception {
        while (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
    
}