#include <bits/stdc++.h>
#include <atcoder/modint>
using namespace std;
using namespace atcoder;
#define reps(i,s,n) for(int i = s; i < n; i++)
#define rep(i,n) reps(i,0,n)
#define Rreps(i,n,e) for(int i = n - 1; i >= e; --i)
#define Rrep(i,n) Rreps(i,n,0)
#define ALL(a) a.begin(), a.end()

using ll = long long;
using vec = vector<ll>;
using mat = vector<vec>;

ll N,M,H,W,Q,K,A,B;
string S;
using P = pair<ll, ll>;
using tp = tuple<ll, ll, ll>;
const ll INF = (1LL<<60);

template<class T> bool chmin(T &a, const T b){
    if(a > b) {a = b; return true;}
    else return false;
}
template<class T> bool chmax(T &a, const T b){
    if(a < b) {a = b; return true;}
    else return false;
}
template<class T> void my_printv(std::vector<T> v,bool endline = true){
    if(!v.empty()){
        for(std::size_t i{}; i<v.size()-1; ++i) std::cout<<v[i]<<" ";
        std::cout<<v.back();
    }
    if(endline) std::cout<<std::endl;
}

using mint = modint998244353;
using vm = vector<mint>;

ll msqrt(ll n){
    ll lb = 0, ub = n + 1;
    while(ub - lb > 1){
        ll cen = lb + ((ub - lb)>>1);
        (cen * cen <= n ? lb : ub) = cen;
    }
    return lb;
}

ll pr(ll n){
    //[1, n)
    if((--n) <= 1) return 0;
    ll sn = msqrt(n);
    vec smalls(n / sn + 1), larges(sn + 1);
    for(int i = 1; i <= sn; ++i) larges[i] = n / i - 1;
    for(int i = 1; i <= n / sn; ++i) smalls[i] = i - 1;
    auto access_inv = [&](int i){
        ll n_i = n / i;
        if(n_i == 0) return 0LL;
        return (n_i <= sn ? smalls[n_i] : larges[i]);
    };
    for(ll p = 2; p <= sn; ++p){
        if(p < n / sn && smalls[p] <= smalls[p - 1]) continue;
        if(p >= n / sn && larges[n / p] <= smalls[p - 1]) continue;
        ll pp = p * p, now_pi = smalls[p - 1];
        for(ll i = 1, ip = p, ipp = pp; ipp <= n && i <= sn; ++i, ip += p, ipp += pp){
            larges[i] -= access_inv(ip) - now_pi;
        }
        for(ll i = n / sn; i >= pp; --i){
            smalls[i] -= smalls[i / p] - now_pi;
        }
    }
    return larges[1];
}

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    //reps(i, 3, 102) if(pr(i) - pr(i) == 1) cout<<i<<endl;
    cin>>A>>B;
    ++B;
    cout<<pr(B) - pr(A) + pr(B * 2 - 1) - pr(A * 2 + 1)<<endl;
}