import java.util.*;
import java.lang.*;

class Main
{
    public static void main (String[] args) throws java.lang.Exception
    {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        int[][] tests = new int[n][2];
        int max = 0;
        for (int i = 0; i < n; i++) {
            tests[i][0] = scanner.nextInt();
            tests[i][1] = scanner.nextInt();
            if (tests[i][1] > max) {
                max = tests[i][1];
            }
        }
        int[] primes = new int[max + 1];
        for (int i = 2; i < max + 1; i++) {
            primes[i] = 1;
        }
        for (int i = 4; i < max + 1; i += 2) {
            primes[i] = 0;
        }
        for (int i = 3; i <= (max + 1) / 2; i += 6) {
            if (primes[i] == 0) {
                continue;
            }
            for (int j = 2 * i; j < max + 1; j += i) {
                primes[j] = 0;
            }
            if (i + 1 < max) {
                if (primes[i] == 0) {
                    continue;
                }
                for (int j = 2 * (i + 2); j < max + 1; j += (i + 2)) {
                    primes[j] = 0;
                }
            }
        }
        for (int i = 1; i < max + 1; i++) {
            primes[i] += primes[i - 1];
        }
        for (int i = 0; i < n; i++) {
            System.out.println(primes[tests[i][1]] - primes[tests[i][0]]);
        }
    }
}