def find_intersection(arr1, arr2):
    intersection = sorted(set(arr1) & set(arr2))
    return intersection if intersection else [-1]
 
def find_union(arr1, arr2):
    union = sorted(set(arr1) | set(arr2))
    return union if union else [-1]
 
def main():
    # Input sizes of arrays
    n, m = map(int, input().split())
 
    # Input arrays
    arr1 = list(map(int, input().split()))
    arr2 = list(map(int, input().split()))
 
    # Find intersection
    intersection = find_intersection(arr1, arr2)
 
    # Find union
    union = find_union(arr1, arr2)
 
    # Print intersection
    print(*intersection)
 
    # Print union
    print(*union)
 
if __name__ == "__main__":
    main()
 

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