#include <bits/stdc++.h>
#include <iostream>
#include <cmath>

using namespace std;

const int maxN = 1e6 + 5;

int prime[maxN];
bool vis13[maxN];// 素数表


void getPrime() {
	memset(vis13, true, sizeof(vis13));

	vis13[0] = vis13[1] = false;
	for (int i = 2; i <= maxN / i; ++i) {
		if (vis13[i]) {
			prime[++prime[0]] = i;
		}
		for (int j = 1; j <= prime[0] && i * prime[j] <= maxN; ++j) {
			vis13[i * prime[j]] = false;
			if (i % prime[j] == 0) {
				break;
			}
		}
	}
}

int FindOneNum(unsigned int n)
{
	int count = 0;
	while (n)
	{
		n &= n - 1;  //将n与n-1异或赋予n
		count++;
	}
	return count;
}

int main(void) {
	getPrime();
	int l, r;
	cin >> l >> r;

	int ans = 0;

	for (int i = l; l <= r; ++l) {
		int temp = FindOneNum(l);
		if (vis13[temp]) {
			ans++;
		}
	}

	cout << ans << endl;

	return 0;
}