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

int main() {
    long long L,R;
    cin >> L >> R;
    vector<long long>tmp(R-L+1);
    for(long long j = L; j <= R; j++) {
        tmp[j-L] = j;
    }
    vector<bool>used(R-L+1);
    for(long long i = 2; i <= 1000000; i++) {
        for(long long j = (L+i-1)/i*i; j <= R; j += i) {
            int cnt = 0;
            while (tmp[j-L]%i == 0) {
                tmp[j-L] /= i;
                cnt++;
            }
            if(cnt >= 2) {
                used[j-L] = true;
            }
        }
    }
    int ans = 0;
    for(long long i = L; i <= R; i++) {
        if(!used[i-L]) {
            long long l = 1,r = 1001001001;
            while (l+1 < r) {
                long long mid = (l+r)/2;
                if(mid*mid >= tmp[i-L]) {
                    r = mid;
                }
                else {
                    l = mid;
                }
            }
            if(r*r != tmp[i-L]) {
                ans++;
            }
        }
    }
    cout << ans << endl;
}