5*+ctlhn                               

def uoc(n):
    s=0
    for i in range(1,int(n**0.5)+1):
        if n%i==0: s+=2
    k=int(n**0.5)
    if k*k==n: s-=1
    return s
a,b=map(int,input().split())
s=0
for i in range(a,b+1):
    if uoc(i)==3:
        s+=1
print(s)

#include <iostream>
#include <cmath>

using namespace std;

int uoc(int n) {
    int s = 0;
    for (int i = 1; i <= sqrt(n); ++i) {
        if (n % i == 0) s += 2;
    }
    int k = static_cast<int>(sqrt(n));
    if (k * k == n) s -= 1;
    return s;
}

int main() {
    int a, b;
    cin >> a >> b;
    int s = 0;
    for (int i = a; i <= b; ++i) {
        if (uoc(i) == 3) {
            s += 1;
        }
    }
    cout << s << endl;
    return 0;
}

#include <bits/stdc++.h>
using namespace std;
bool check(int x){
	int sq=sqrt(x);
	if(sq*sq!=x)return false;
	for(int i=2;i<=sq;i++){
		if(x%i==0){
			return false;
		}
	}
	return true;
}
signed main(){
	ios_base::sync_with_stdio(0);
	int a,b;
	cin>>a>>b;
	int ans=0;
	while(a<=b){
		if(check(a)){
			++ans;
		}
		++a;
	}
	cout<<ans;
}