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

int prime(ll n){
    if(n==1) return 0;
    ll raiz = sqrt(n)+1;
    for(ll i = 2; i<raiz; i++){
        if(n%i==0){
            return 0;
            break;
        }
    }
    return 1;
}
int main() {
    int t;
    ll a, b, s = 0;
    cin>>t;
    double aux;
    ll aux2=0;
    while(t>0){
        cin>>a>>b;
        s = 0;
        for(int i= a;i<=b;i++){
            aux = sqrt(i);
            if(pow(aux, 2)==i){
                aux2 = (int)aux;
                if(prime(aux2)){
                    s++;
                }
            }
        }
        cout<<s<<"\n";
        t--;
    }
}