import java.util.*;
 
public class Main {
 
    public static Map<Integer, Integer> getFrequencyMap(int[] arr) {
        Map<Integer, Integer> frequencyMap = new HashMap<>();
        for (int num : arr) {
            frequencyMap.put(num, frequencyMap.getOrDefault(num, 0) + 1);
        }
        return frequencyMap;
    }
 
    public static int getFrequency(Map<Integer, Integer> frequencyMap, int num) {
        return frequencyMap.getOrDefault(num, 0);
    }
 
    public static void main(String[] args) {
        int[] arr = {1, 3, 2, 4, 2, 1};
        Map<Integer, Integer> frequencyMap = getFrequencyMap(arr);
 
        System.out.println(getFrequency(frequencyMap, 2));
        System.out.println(getFrequency(frequencyMap, 3));
        System.out.println(getFrequency(frequencyMap, 5));
    }
}
 

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