#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
typedef pair<ll, ll> p_ll;

template<class T>
void debug(T itr1, T itr2) { auto now = itr1; while(now<itr2) { cout << *now << " "; now++; } cout << endl; }
#define repr(i,from,to) for (ll i=(ll)from; i<(ll)to; i++)
#define all(vec) vec.begin(), vec.end()
#define rep(i,N) repr(i,0,N)
#define per(i,N) for (int i=(int)N-1; i>=0; i--)

const ll MOD = pow(10,9)+7;
const ll LLINF = pow(2,61)-1;
const int INF = pow(2,30)-1;

vector<ll> fac;
void c_fac(int x=pow(10,6)+10) { fac.resize(x,true); rep(i,x) fac[i] = i ? (fac[i-1]*i)%MOD : 1; }
ll modpow(ll x, ll p) { ll result = 1, now = 1, pm = x; while (now<=p) { if (p&now) { result = result * pm % MOD; } now*=2; pm = pm*pm % MOD; } return result; }
ll inv(ll a, ll m=MOD) { ll b = m, x = 1, y = 0; while (b!=0) { int d = a/b; a -= b*d; swap(a,b); x -= y*d; swap(x,y); } return (x+m)%m; }
ll nck(ll n, ll k) { return fac[n]*inv(fac[k]*fac[n-k]%MOD)%MOD; }
ll gcd(ll a, ll b) { if (a<b) swap(a,b); return b==0 ? a : gcd(b, a%b); }
ll lcm(ll a, ll b) { return a/gcd(a,b)*b; }

vector<ll> prime;

void calc_prime(ll N) {
  prime.resize(N+1,true);
  prime[0] = false; prime[1] = false;
  for (ll i=2; i<=N; i++) {
    if (!prime[i]) continue;
    for (ll j=2; i*j<=N; j++) prime[i*j] = false;
  }
}

bool issq(ll N) {
  ll l = 1, r = pow(10,9);
  while (l!=r) {
    ll mid = (l+r+1)/2;
    if (mid*mid<=N) l = mid;
    else r = mid-1;
  }
  return l*l==N;
}

ll MA = pow(10,6);

int main() {
  ll L, R; cin >> L >> R;
  calc_prime(MA);
  // debug(all(prime)); debug(all(sqfree));

  ll N = R-L+1;
  vector<ll> num(N); rep(i,N) num[i] = L+i;
  rep(i,MA+1) {
    if (!prime[i]) continue;
    for (ll j=(L+(i-1))/i; i*j<=R; j++) {
      ll cnt = 0;
      while (num[i*j-L]%i==0) {
        cnt++; num[i*j-L] /= i;
      }
      if (cnt>=2) num[i*j-L] = -1;
    }
  }
  // debug(all(num));

  ll result = 0;
  rep(i,N) result += num[i]!=-1 && (num[i]==1||!issq(num[i]));
  cout << result << endl;
  return 0;
}