[백준/자바] 1978 - 소수 찾기

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int N = Integer.parseInt(br.readLine());

        int result = 0;

        StringTokenizer st = new StringTokenizer(br.readLine());
        for (int i = 0; i < N; i++) {
            int num = Integer.parseInt(st.nextToken());

            boolean isPrime = true;

            if (num == 1) continue;

            for (int j = 2; j <= Math.sqrt(num); j++) {
                if (num % j == 0) {
                    isPrime = false;
                    break;
                }
            }

            if (isPrime) result++;
        }

        System.out.println(result);
    }
}