#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define all(x) (x).begin(),(x).end()
const long long MOD = 1000000007;
const long long INF = 9*1e18;
using ll = long long;
using mint = modint1000000007;
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 (b<a) { a=b; return 1; } return 0; }
long double PI = 3.14159265358979;

vector<ll> primelist;

bool Prime(ll num)
{
    if (num < 2) return false;
    else if (num == 2) return true;
    else if (num % 2 == 0) return false;
 
    double sqrtNum = sqrt(num);
    for (ll i = 3; i <= sqrtNum; i += 2)
    {
        if (num % i == 0)
        {
            return false;
        }
    }
    return true;
}

void primeinput(){
  for(ll i = 2;i<1002000;i++){
    if(Prime(i)){
      primelist.push_back(i);
    }
  }
}



int main(){
  ios::sync_with_stdio(false);
  std::cin.tie(nullptr);
  ll L,R;
  cin>>L>>R;
  primeinput();
  vector<ll> A,B;
  for(ll i = L;i<=R;i++){
    A.push_back(i);
    B.push_back(0);
  }
  rep(i,primelist.size()){
    ll temp = 0;
    if(primelist[i]  >= L){
      temp = primelist[i]-L;
    }
    else{
      temp = (L%primelist[i]);
    }
    while(temp <(R-L)){
      ll cnt = 0;
      while(A[temp]%primelist[i] == 0){
        A[temp]/=primelist[i];
        cnt++;
      }
      if(cnt >= 2){
        B[temp] = 1;
      }
      temp += primelist[i];
    }
  }
  /*rep(i,B.size()){
    cout << B[i] << " ";
  }
  cout << endl;*/
  ll ans = 0;
  rep(i,A.size()){
    if(B[i] == 1){
      continue;
    }
    if(A[i] == 1){
      ans++;
      continue;
    }
    ll temp = sqrt(A[i]);
    //cout << temp << endl;
    bool d = 0;
    for(int k = -2;k<=3;k++){
      if((temp+k)*(temp+k) == A[i]){
        d = 1;
      }
    }
    if(!d){
      ans++;
    }
  }
  cout << ans << endl;
  return 0;
}