You are hanging around in hostel when a person approaches you.
"Leaving the bald people aside, I can bet a hundred bucks that there are two people living in this hostel who have same number of hairs on their heads," he says to you.
You say that you will take the bet. After talking to the man for a couple of minutes, you realize that you have lost the bet.
What did the person say to you that proved his statement ?