#include <bits/stdc++.h>
using namespace std;

namespace sieve {

std::vector<int> primes, lpf;
void init(int n) {
  if (n < int(std::size(lpf))) return;
  if (n < 2 * int(std::size(lpf))) n = 2 * std::size(lpf);
  lpf.resize(n + 1, -1);
  for (int d = 2; d <= n; ++d) {
    if (lpf[d] == -1) lpf[d] = d, primes.push_back(d);
    for (int p : primes) {
      if (p * d > n or p > lpf[d]) break;
      lpf[p * d] = p;
    }
  }
}

}  // namespace sieve

int main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  int64_t l, r;
  cin >> l >> r;
  sieve::init(1e6);

  vector<int64_t> num(r - l + 1);
  iota(begin(num), end(num), l);

  vector<vector<int64_t>> factor(r - l + 1);

  for (int p : sieve::primes) {
    for (auto i = r / p * p; i >= l; i -= p) {
      while (num[i - l] % p == 0) {
        num[i - l] /= p;
        factor[i - l].push_back(p);
      }
    }
  }

  int ans = 0;
  for (auto i = l; i <= r; ++i) {
    if (adjacent_find(begin(factor[i - l]), end(factor[i - l])) != end(factor[i - l])) {
      continue;
    }

    if (num[i - l] > 1) {
      if (int64_t t = sqrtl(num[i - l]); t * t == num[i - l]) {
        continue;
      }
    }

    ++ans;
  }
  cout << ans << '\n';
}