Hackerearth Alphaprime problem

import java.util.*;
import java.io.*;
class AlphaPrimes
{
    //DONT FORGET TO COMMIT AND PUSH TO GITHUB
    static int MAX = (int)1e6 + 10;
    static boolean isComposite[]  = isCompositeArray(MAX);
    static int numOfAlphaPrimes[] = new int[MAX];
    private static void preCalculate()
    {
        for(int i=1;i<=MAX-1;i++)
        {
            if(isAlphaPrime(i))
                numOfAlphaPrimes[i] = numOfAlphaPrimes[i-1] + 1;
            else
                numOfAlphaPrimes[i] = numOfAlphaPrimes[i-1];
        }
    }
    public static boolean[] isCompositeArray(int N)     //Sieve of Erathanoses
    {
        boolean num[] = new boolean[N+1];
        num[1]=true;
        num[0]=true;
        int end = (int)Math.sqrt(N);
        for(int i=2;i<=end;i++)
        {
            if(!num[i])
                for(int j=i*i;j<num.length;j+=i)
                    num[j] = true;
        }

        return num;
    }
    private static boolean isAlphaPrime(int n)
    {

        if(!isComposite[n])
            return true;
        else
        {
            while(true)
            {
                if(n < 10)
                {
                    return !isComposite[n];
                }
                else
                {
                    n = Integer.parseInt(Integer.toString(n).substring(1));
                    if(!isComposite[n])
                        return true;
                }
            }
        }

    }
    private static void solve(FastScanner s1, FastWriter out)/* This is the actual solution */{
        int t = s1.nextInt();
        preCalculate();
        //out.println(Arrays.toString(numOfAlphaPrimes));
        while(t-->0)
        {
            int l =s1.nextInt();
            int r = s1.nextInt();
                out.println(numOfAlphaPrimes[r]-numOfAlphaPrimes[l-1]);
        }
    }

    /************************ TEMPLATE STARTS HERE ************************/

    public static void main(String []args) throws IOException {
        FastScanner in  = new FastScanner(System.in);
        FastWriter  out = new FastWriter(System.out);
        solve(in, out);
        in.close();
        out.close();
    }

    static class FastScanner{
        public BufferedReader reader;
        public StringTokenizer st;
        public FastScanner(InputStream stream){
            reader = new BufferedReader(new InputStreamReader(stream));
            st = null;
        }
        public String next(){
            while(st == null || !st.hasMoreTokens()){
                try{
                    String line = reader.readLine();
                    if(line == null) return null;
                    st = new StringTokenizer(line);
                }catch (Exception e){
                    throw (new RuntimeException());
                }
            }
            return st.nextToken();
        }
        public String nextLine(){
            String str = null;
            try {
                str = reader.readLine();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return str;
        }
        public int nextInt(){
            return Integer.parseInt(next());
        }
        public long nextLong(){
            return Long.parseLong(next());
        }
        public double nextDouble(){
            return Double.parseDouble(next());
        }
        int[] nextIntArray(int n) {
            int[] arr = new int[n];
            for (int i = 0; i < n; i++) {
                arr[i] = nextInt();
            }
            return arr;
        }

        long[] nextLongArray(int n) {
            long[] arr = new long[n];
            for (int i = 0; i < n; i++) {
                arr[i] = nextLong();
            }
            return arr;
        }
        public void close(){
            try{ reader.close(); } catch(IOException e){e.printStackTrace();}
        }
    }
    static class FastWriter{
        BufferedWriter writer;
        public FastWriter(OutputStream stream){
            writer = new BufferedWriter(new OutputStreamWriter(stream));
        }
        public void print(int i) {
            print(Integer.toString(i));
        }
        public void println(int i) {
            print(Integer.toString(i));
            print('\n');
        }
        public void print(long i) {
            print(Long.toString(i));
        }
        public void println(long i) {
            print(Long.toString(i));
            print('\n');
        }
        public void print(double i) {
            print(Double.toString(i));
        }
        public void print(boolean i) {
            print(Boolean.toString(i));
        }
        public void print(char i) {
            try{writer.write(i);} catch(IOException e){e.printStackTrace();}
        }
        public void print(String s){
            try{writer.write(s);} catch(IOException e){e.printStackTrace();}
        }
        public void println(String s){
            try{writer.write(s);writer.write('\n');} catch(IOException e){e.printStackTrace();}
        }
        public void println(){
            try{writer.write('\n');} catch(IOException e){e.printStackTrace();}
        }
        public void print(int arr[])
        {
            for (int i = 0; i < arr.length; i++) {
                print(arr[i]);
                print(' ');
            }
        }
        public void close(){
            try{writer.close();} catch(IOException e){e.printStackTrace();}
        }
    }

    /************************ TEMPLATE ENDS HERE ************************/
}