import java.util.*;

class GFG {

static void firstNonRepeating(int arr[], int n)

{

// Insert all array elements in hash

// table

Map<Integer, Integer> m = new HashMap<>();

for (int i = 0; i < n; i++) {

if (m.containsKey(arr[i])) {

m.put(arr[i], m.get(arr[i]) + 1);

}

else {

m.put(arr[i], 1);

}

}

// Traverse through map only and

// using for-each loop for iteration over Map.entrySet()

for (Map.Entry<Integer, Integer> x : m.entrySet())

if (x.getValue() == 1)

System.out.print(x.getKey() + " ");

}

// Driver code

public static void main(String[] args)

{

int arr[] = { 9, 4, 9, 6, 7, 4 };

int n = arr.length;

firstNonRepeating(arr, n);

}

}