#include <iostream>
#include <string>
#include <algorithm>
#include <functional>
#include <vector>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <cstdio>
#include <cmath>
#include <cassert>
#include <tuple>
#define rep(i, n) for(i = 0; i < n; i++)
#define int long long
using namespace std;

int l, r;
bool isPrime[1000001];
bool ng[1000001];	//ng[i] = l + iがsquarefreeならfalse, そうでないならtrue

signed main() {
	int i;
	
	cin >> l >> r;
	
	int unti = 1000000;
	for (i = 2; i <= unti; i++) isPrime[i] = true;
	for (i = 2; i <= unti; i++) {
		if (isPrime[i]) {
			for (int j = i * 2; j <= unti; j += i) {
				isPrime[j] = false;
			}
		}
	}
	
	for (i = 2; i <= unti; i++) {
		if (isPrime[i]) {
			int num = ((l + i * i - 1) / (i * i)) * i * i;
			while (num <= r) {
				ng[num - l] = true;
				num += i * i;
			}
		}
	}
	
	//平方数p^2として、p>10^6. l <= px <= rなるxは1つかつ、x < 10^6
	int snuke = 1000000;
	for (int x = snuke; x >= 1; x--) {
		int low = sqrt((long double)l / x) - 1;
		int high = sqrt((long double)r / x) + 1;
		for (int p = low; p <= high; p++) {
			if (p <= 1) continue;
			int num = p * p * x;
			if (l <= num && num <= r) {
				ng[num - l] = true;
			}
		}
	}
	
	int cnt = 0;
	for (i = 0; i <= r - l; i++) {
		if (ng[i] == false) {
			cnt++;
		}
	}
	cout << cnt << endl;
	return 0;
}