#pragma GCC optimize("O3")
#include<bits/stdc++.h> 
using namespace std;
using ll=long long;
using P=pair<ll,ll>;
template<class T> using V=vector<T>; 
#define fi first
#define se second
#define all(v) (v).begin(),(v).end()
const ll inf=(1e18);
//const ll mod=998244353;
const ll mod=1000000007;
const vector<int> dy={-1,0,1,0},dx={0,-1,0,1};
ll GCD(ll a,ll b) {return b ? GCD(b,a%b):a;}
ll LCM(ll c,ll d){return c/GCD(c,d)*d;}
struct __INIT{__INIT(){cin.tie(0);ios::sync_with_stdio(false);cout<<fixed<<setprecision(20);}} __init;
template<class T> bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T> bool chmin(T &a, const T &b) { if (a>b) { a=b; return 1; } return 0; }
template<class T>void debag(const vector<T> &a){cerr<<"debag :";for(auto v:a)cerr<<v<<" ";cerr<<"\n";}
template<class T>void print(const vector<T> &a){for(auto v:a)cout<<v<<" ";cout<<"\n";}
vector<bool> prime;
V<ll> p;
void make(int num){
    prime.resize(num,true);
    prime[0]=false;
    for(int i=0;i<num;i++){
        if(prime[i]){
              p.emplace_back(i+1);
            for(int j=2;(i+1)*j<=num;j++){
                prime[(i+1)*j-1]=false;
            }
        }
    }
}
int main(){
      make(1000005);
      ll L,R;
      cin>>L>>R;
      V<ll> res(R-L+2,0);
      for(ll i=L;i<=R;i++)res[i-L]=i;
      V<bool> ng(R-L+2,false);
      for(ll v:p){
            for(ll j=(L+v-1)/v*v;j<=R;j+=v){
                 res[j-L]/=v;
                  if(j%(v*v)==0){
                        ng[j-L]=true;
                  }
            }
      }
      ll ans=0;
      for(ll i=L;i<=R;i++){
            if(!ng[i-L]&&res[i-L]==1){
                  ans++;
            }else if(!ng[i-L]){
                  ll l=1,r=ll(1e9)+5;
                  while(r-l>1){
                        ll mid=(l+r)/2;
                        if(mid*mid>res[i-L])r=mid;
                        else l=mid;
                  }
                  if(l*l!=res[i-L])ans++;
            }
      }
      cout<<ans<<"\n";
}