#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using uint = unsigned int;
using ull = unsigned long long;
#define rep(i,n) for(int i=0;i<int(n);i++)
#define rep1(i,n) for(int i=1;i<=int(n);i++)
#define per(i,n) for(int i=int(n)-1;i>=0;i--)
#define per1(i,n) for(int i=int(n);i>0;i--)
#define all(c) c.begin(),c.end()
#define si(x) int(x.size())
#define pb emplace_back
#define fs first
#define sc second
template<class T> using V = vector<T>;
template<class T> using VV = vector<vector<T>>;
template<class T,class U> void chmax(T& x, U y){if(x<y) x=y;}
template<class T,class U> void chmin(T& x, U y){if(y<x) x=y;}
template<class T> void mkuni(V<T>& v){sort(all(v));v.erase(unique(all(v)),v.end());}
template<class T> int lwb(const V<T>& v, const T& a){return lower_bound(all(v),a) - v.begin();}
template<class T>
V<T> Vec(size_t a) {
    return V<T>(a);
}
template<class T, class... Ts>
auto Vec(size_t a, Ts... ts) {
  return V<decltype(Vec<T>(ts...))>(a, Vec<T>(ts...));
}
template<class S,class T> ostream& operator<<(ostream& o,const pair<S,T> &p){
	return o<<"("<<p.fs<<","<<p.sc<<")";
}
template<class T> ostream& operator<<(ostream& o,const vector<T> &vc){
	o<<"{";
	for(const T& v:vc) o<<v<<",";
	o<<"}";
	return o;
}
constexpr ll TEN(int n) { return (n == 0) ? 1 : 10 * TEN(n-1); }

#ifdef LOCAL
#define show(x) cerr << "LINE" << __LINE__ << " : " << #x << " = " << (x) << endl
void dmpr(ostream& os){os<<endl;}
template<class T,class... Args>
void dmpr(ostream&os,const T&t,const Args&... args){
	os<<t<<" ~ ";
	dmpr(os,args...);
}
#define shows(...) cerr << "LINE" << __LINE__ << " : ";dmpr(cerr,##__VA_ARGS__)
#define dump(x) cerr << "LINE" << __LINE__ << " : " << #x << " = {";  \
	for(auto v: x) cerr << v << ","; cerr << "}" << endl;
#else
#define show(x) void(0)
#define dump(x) void(0)
#define shows(...) void(0)
#endif
V<bool> isp;
V<int> pr;
V<int> sf; //smallest factor, sf[9*5*11] = 3
void linear_sieve(int X){		// <= X
	isp = V<bool>(X+1,true); isp[0] = isp[1] = false;
	sf = V<int>(X+1);
	for(int i=2;i<=X;i++){
		if(isp[i]){
			pr.pb(i);
			sf[i] = i;
		}
		for(int j=0;i*pr[j]<=X;j++){
			isp[i*pr[j]] = false;
			sf[i*pr[j]] = pr[j];
			if(i%pr[j] == 0) break;
		}
	}
}

const ll X = 1000010;
ll f[X];
bool sq[X];

int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);		//DON'T USE scanf/printf/puts !!
	cout << fixed << setprecision(20);

	linear_sieve(X);

	ll L,R; cin >> L >> R;
	rep(i,R-L+1){
		f[i] = L+i;
	}
	for(ll p: pr){
		for(ll x=(L+p-1)/p*p; x<=R; x+=p){
			f[x-L] /= p;
			while(f[x-L]%p == 0){
				f[x-L] /= p;
				sq[x-L] = true;
			}
		}
	}
	ll ans = 0;
	rep(i,R-L+1){
		if(f[i] > 1){
			ll r = sqrtl(f[i]);
			if(r*r == f[i]) sq[i] = true;
		}
		if(!sq[i]) ans++;
	}
	cout << ans << endl;
}