Smeagol is a very brilliant creature! In his spare time, he figured out that without any calculators! With this brilliant knowledge, he decided to play a "game" with Bilbo Baggins, who is lost in Smeagol's cave. In this "game", Bilbo has to find the smallest such that . If Bilbo finds the correct , Smeagol must lead him out of the cave. Otherwise, Bilbo becomes Smeagol's lunch. What should Bilbo choose to guarantee his safe passage out of the cave?