#include <iostream>
#include <vector>
#include <cmath>

using namespace std;
typedef long long ll;
ll p[1000010];
int main(){
    ll i,j,l,r; cin >> l >> r;
    vector<ll> v;
    for(i=l;i<=r;i++) v.push_back(i); //v[i] = l + i
    for(i=2;i<=1000000;i++){
        ll ll = (l + i - 1)/i*i; //ll,ll + i,ll + 2*i...
        for(j=ll;j<=r;j+=i){
            if(v[j - l]!=0 && v[j - l]%i==0){
                int cnt = 0;
                while(v[j - l]%i==0){
                    //cout << v[j - l] << " " << i << endl;
                    v[j - l] /= i; cnt++;
                }
                if(cnt>=2) v[j - l] = 0;
            }
        }
    }
    /*for(i=l;i<=r;i++) cout << i << " ";
    cout << endl;
    for(ll x:v) cout << x << " ";
    cout << endl;*/
    int cnt = v.size();
    for(ll x:v){
        if(x==1) continue;
        if(x==0) cnt--;
        else{
            ll y = sqrt(x);
            if(x==y*y) cnt--;
        } 
    }
    cout << cnt << endl;
}