# List of known perfect numbers (first few)
perfect_numbers = {6, 28, 496, 8128, 33550336, 8589869056, 137438691328, 2305843008139952128}

def is_perfect_number(N):
    return N in perfect_numbers

# Example usage:
N = 28  # 28 is a perfect number
print(is_perfect_number(N))  # Output: True

N = 12  # 12 is not a perfect number
print(is_perfect_number(N))  # Output: False