One morning, when I was leaving for my business, a middle-aged man came up and asked me for help. He said he had no 1 to get food for his large family.

    You look 2. Why don't you work？" I asked." Simply because I cannot get work，sir.""If I give you work, what you want?" "3 I can get bread for my family, sir." he answered.

    I decided to find out if he  4 meant what he said. "OK. I'll give you one pound an hour, if you will 5   a brick(砖)under your arm and walk around the square for five hours without stopping. ""Thank you, sir. I will. "

    I found a brick and started him on his walk before I went to my 6. I never thought he would he had 7.

    When I came back five hours later, I saw him 8 walking, with the brick under his arm.

    I stopped him and gave him 9 pounds. He thanked me and told me that some people had 10 to help him when they knew why he was doing all this. He would go and ask 11 for work. Before leaving, he asked if I would give him the 12.I did.

    Several years later, a well-dressed man greeted me on a train. Seeing I was not sure who he was, he 13 that he was the brick man and had his own business now. "You know, I still keep that brick and always value it as the most 14 thing I have as it has brought me luck and success."

    15, it was not the brick that made the man successful, but his faithfulness(坚定) in doing even a very little thing.

  在实数0，-π，$\sqrt{3}$，-4中，最小的数是（  ）