Three wise men approach their Master to decide who is the wisest of them. The Master agrees to resolve the dispute through a simple test. "I will blindfold all of you and paint either a red or a blue dot on each man's forehead. Then, I will take your blindfolds off. If you see at least one red dot, raise your hand. The one, who guesses the color of the dot on his forehead first, wins."
The Master blindfolded the three and painted the dots. When he took their blindfolds off, all the three men raised their hands as each of them could see at least one red dot. After a lot of thought, the first of them accepted defeat saying he could not guess the colour of the dot on his forehead. After some time, the second too conceded defeat. After hearing their responses and thinking for a while, the third answered that he had a red dot on his forehead, and he was right. How did he guess?