#include<bits/stdc++.h>

using namespace std;

#pragma GCC optimize("Ofast")

#define ll long long
#define ld long double
#define rep(i, a, b) for (int i = a; i < b; i++)
#define rep1(i, a, b) for (int i = (b) - 1; i >= a; i--)
#define endl '\n'
#define vvii vector<vector<int>>
#define vi vector<int>
#define vvll vector<vector<ll>>
#define vl vector<ll>

template<class T> ostream& operator << (ostream &s, vector<T> &P)
{ for (int i = 0; i < P.size(); ++i) { if (i > 0) { s << " "; } s << P[i]; } return s; }

template <class T>bool chmax(T &a, T b){if (a < b){a = b;return true;}return false;}
template <class T>bool chmin(T &a, T b){if (a > b){a = b;return true;}return false;}

template <class T = int>T gcd(T a, T b){return (b == 0) ? a : gcd(b, a % b);}
template <class T = int>T lcm(T a, T b){return a / gcd(a, b) * b;}
template<class T = int>T powMod(T x, T k, T m) {if (k == 0){return (T)1;}if (k % 2 == 0) {return powMod(x*x % m, k/2, m);}else{return x*powMod(x, k-1, m) % m;}}
template <class T = int>T extgcd(T a,T b,T &x,T &y){T g = a;x = 1;y = 0;if (b != 0) {g = extgcd(b, a % b, y, x), y -= (a / b) * x;}return g;}
template<class T = int> T invMod(T a,T m){T x,y;if (extgcd(a, m, x, y) == 1) {return (x + m) % m;}else{return -1;}}

using Pii  = pair<int,int>;
using Pll = pair<ll,ll>;

struct Eratos
{
    vector<int> primes;
    vector<bool> isprime;
    vector<int> mebius;
    vector<int> min_factor;

    Eratos(int MAX) : primes(),
                    isprime(MAX + 1, true),
                    mebius(MAX + 1, 1),
                    min_factor(MAX + 1, -1)
    {
        isprime[0] = isprime[1] = false;
        min_factor[0] = 0, min_factor[1] = 1;
        for (int i = 2; i <= MAX; ++i)
        {
            if (!isprime[i])
                continue;
            primes.push_back(i);
            mebius[i] = -1;
            min_factor[i] = i;
            for (int j = i * 2; j <= MAX; j += i)
            {
                isprime[j] = false;
                if ((j / i) % i == 0)
                    mebius[j] = 0;
                else
                    mebius[j] = -mebius[j];
                if (min_factor[j] == -1)
                    min_factor[j] = i;
            }
        }
    }

    // prime factorization
    vector<pair<int, int>> prime_factors(int n)
    {
        vector<pair<int, int>> res;
        while (n != 1)
        {
            int prime = min_factor[n];
            int exp = 0;
            while (min_factor[n] == prime)
            {
                ++exp;
                n /= prime;
            }
            res.push_back(make_pair(prime, exp));
        }
        return res;
    }

    // enumerate divisors
    vector<int> divisors(int n)
    {
        vector<int> res({1});
        auto pf = prime_factors(n);
        for (auto p : pf)
        {
            int n = (int)res.size();
            for (int i = 0; i < n; ++i)
            {
                int v = 1;
                for (int j = 0; j < p.second; ++j)
                {
                    v *= p.first;
                    res.push_back(res[i] * v);
                }
            }
        }
        return res;
    }
};
const int maxn = 1e6 + 10;
Eratos Primes(maxn);

bool is_square(ll x){
    ll l = 1; //l * l <= x
    ll r = 1e9 + 5; // l * l > x
    while (r - l > 1){
        ll med = (r + l) / 2;
        if (med * med <= x){
            l = med;
        }else{
            r = med;
        }
    }
    if (l * l == x){
        return true;
    }else{
        return false;
    }
}

signed main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    
    ll L,R;
    cin >> L >> R;
    vector<ll> valid(R - L + 1);
    vector<bool> ok(R - L + 1);
    for (ll i = 0; i <= R - L;i++){
        valid[i] = i + L;
        ok[i] = true;
    }
    for (int p : Primes.primes){
        ll q = p;
        for (ll d = (L + q - 1) / q * q; d <= R;d += q){
            int ord = 0;
            while(valid[d - L] % q == 0){
                valid[d - L] /= q;
                ord++;
            }
            if (ord >= 2){
                ok[d - L] = false;
            }
        }
    }
    int ans = 0;
    for (ll i = 0; i <= R - L;i++){
        if (!ok[i]){
            continue;
        }
        ans++;
        ll x = valid[i];
        if (is_square(x)  && x > 1){
            ans--;
        }
    }
    cout << ans << endl;
    return 0;
}