#include <iostream>
#include <vector>
#include <algorithm>

std::vector<int> sieve(int n)
{
    std::vector<int> is_prime(n + 1, 1);

    is_prime[0] = 0;
    is_prime[1] = 0;

    for (int i = 2; i * i <= n; i++) {
        if (is_prime[i]) {
            for (int j = i * i; j <= n; j += i) {
                is_prime[j] = 0;
            }
        }
    }

    return is_prime;
}

int main(void)
{
    int n;
    std::cin >> n;

    std::vector<std::pair<int, int>> intervals;

    int m = 0;
    for (int i = 0; i < n; i++) {
        int a, b;
        std::cin >> a >> b;
        m = std::max(m, b);
        intervals.push_back(std::make_pair(a, b));
    }

    auto primes = sieve(m);

    for (int i = 1; i <= m; i++) {
        primes[i] += primes[i - 1];
    }

    for (int i = 0; i < n; i++) {
        auto [a, b] = intervals[i];
        std::cout << primes[b] - primes[a - 1] << std::endl;
    }

    return 0;
}