#include"bits/stdc++.h"
using namespace std;
#define ALL(x) begin(x),end(x)
#define rep(i,n) for(int i=0;i<(n);i++)
#define debug(v) cout<<#v<<":";for(auto x:v){cout<<x<<' ';}cout<<endl;
#define mod 1000000007
using ll=long long;
const int INF=1000000000;
const ll LINF=1001002003004005006ll;
int dx[]={1,0,-1,0},dy[]={0,1,0,-1};
// ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
template<class T>bool chmax(T &a,const T &b){if(a<b){a=b;return true;}return false;}
template<class T>bool chmin(T &a,const T &b){if(b<a){a=b;return true;}return false;}

struct IOSetup{
    IOSetup(){
        cin.tie(0);
        ios::sync_with_stdio(0);
        cout<<fixed<<setprecision(12);
    }
} iosetup;
 
template<typename T>
ostream &operator<<(ostream &os,const vector<T>&v){
    for(int i=0;i<(int)v.size();i++) os<<v[i]<<(i+1==(int)v.size()?"":" ");
    return os;
}
template<typename T>
istream &operator>>(istream &is,vector<T>&v){
    for(T &x:v)is>>x;
    return is;
}

signed main(){
    ll L,R;cin>>L>>R;R++;

    ll W=R-L;
    set<ll> ban;
    for(ll i=2;i*i<=W+1029418;i++){
        ll p=i*i;

        ll st=((p+L-1)/p)*p;
        for(ll t=st;t<R;t+=p) ban.insert(t);
    }

    ll S;
    {
        ll lw=1,hi=1000000000;
        while(lw<=hi){
            ll mid=(lw+hi)/2;
            if(L<=mid*mid) S=mid,hi=mid-1;
            else           lw=mid+1;
        }
    }
    ll T;
    {
        ll lw=1,hi=1000000000;
        while(lw<=hi){
            ll mid=(lw+hi)/2;
            if(mid*mid<=R) T=mid,lw=mid+1;
            else           hi=mid-1;
        }
    }
    for(ll t=S;t<=T;t++)if(L<=t*t and t*t<R and t!=1) ban.insert(t*t);
    cout<<W-(ll)ban.size()<<endl;
    return 0;
}