#include<bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
using mint=modint998244353; //1000000007;
using ll=long long;
using pp=pair<int,int>;
#define sr string 
#define vc vector
#define fi first
#define se second
#define rep(i,n) for(int i=0;i<(int)n;i++)
#define pb push_back
#define all(v) v.begin(),v.end()
#define pque priority_queue
#define bpc(a) __builtin_popcount(a)
ll root(ll a){
  ll wa=1,ac=1e9;
  while(ac-wa>1){
    ll x=(ac+wa)/2;
    if(x*x>=a)ac=x;
    else wa=x;
  }
  return ac;
}
int main(){
  ll l,r;cin>>l>>r;
  ll n=r-l+1;
  vc<ll>v(n),ch(n,0); for(ll i=0;i<n;i++)v[i]=i+l;
  for(ll i=2;i<=1e6;i++)for(ll j=(l+i-1)/i*i;j<=r;j+=i){
    int t=0;
    while(v[j-l]%i==0)v[j-l]/=i,t++;
    if(t>1)ch[j-l]=1;
  }
  rep(i,n)if(!ch[i]){
    ll x=root(v[i]);
    if(x*x==v[i])ch[i]=1;
  }
  int ans=0;
  rep(i,n)ans+=ch[i];
  //cout<<root(1000000)<<"\n";
  ans=n-ans;
  cout<<ans;
}