#include "bits/stdc++.h" //#include "atcoder/all" using namespace std; //using namespace atcoder; //using mint = modint1000000007; //const int mod = 1000000007; //using mint = modint998244353; //const int mod = 998244353; const int INF = 1e9; //const long long LINF = 1e18; //const bool debug = false; #define rep(i, n) for (int i = 0; i < (n); ++i) #define rep2(i,l,r)for(int i=(l);i<(r);++i) #define rrep(i, n) for (int i = (n-1); i >= 0; --i) #define rrep2(i,l,r)for(int i=(r-1);i>=(l);--i) #define all(x) (x).begin(),(x).end() #define allR(x) (x).rbegin(),(x).rend() #define endl "\n" #define P pair template inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; } template inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; } //エラトステネスの篩(素数の数を返している) //11→2,3,5,7,11 vector sieve(long long n = 1000000) { vectorp(n + 1, true); vectorret; p[0] = false; p[1] = false; for (int i = 2; i <= n; ++i) { if (p[i]) { ret.push_back(i); for (int j = 2 * i; j <= n; j += i) p[j] = false; } } return ret; } bool squarefree(long long n) { long long ng = 0; long long ok = INF; while (1 < abs(ok - ng)) { long long c = (ng + ok) / 2; if (n <= (c * c)) ok = c; else ng = c; } bool ret = false; if (n == ok * ok)ret = true; return ret; } int main() { ios::sync_with_stdio(false); cin.tie(nullptr); long long l, r; cin >> l >> r; auto p = sieve(); vectorx(r - l + 1); rep(i, x.size()) x[i] = l + i; rep(i, p.size()) { long long pri = p[i]; long long fir = ((l + (pri - 1)) / pri) * pri; if (r < fir)continue; for (; fir <= r; fir += pri) { long long idx = fir - l; if (0 == (x[idx] % (pri * pri)))x[idx] = 0; else if (0 == (x[idx] % pri))x[idx] /= pri; } } int ans = 0; rep(i, x.size()) { if (0 == x[i])continue; else if (1 == x[i])ans++; else ans += 1 - squarefree(x[i]); } cout << ans << endl; return 0; }