How did Pharaoh respond when Moses and Aaron first told him to let Israel go?

Answer: "Who is the LORD, that I should obey?"

"Who is the LORD that I should obey His voice and let Israel go? I do not know the LORD, and I will not let Israel go."

“But Pharaoh replied, “Who is the LORD that I should obey His voice and let Israel go? I do not know the LORD, and I will not let Israel go.””— Exodus 5:2 (BSB)