Untitled

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

const int MAXN = 10000000;
vector<int> pr(MAXN + 1, 0);
vector<int> prime_count(MAXN + 1, 0);

void sieve() {
    pr[0] = pr[1] = 1;
    for (int i = 2; i * i <= MAXN; i++) {
        if (pr[i] == 0) {
            for (int j = i * i; j <= MAXN; j += i) {
                pr[j] = 1;
            }
        }
    }

    for (int i = 1; i <= MAXN; i++) {
        prime_count[i] = prime_count[i - 1] + (pr[i] == 0 ? 1 : 0);
    }
}

int main() {
    sieve();

    int q;
    cin >> q;
    while (q--) {
        int L, R;
        cin >> L >> R;
        cout << prime_count[R] - prime_count[L - 1] << "\n";
    }
    
    return 0;
}