Z城市居住着很多只跳蚤。在Z城市周六生活频道有一个娱乐节目。一只跳蚤将被请上一个高空钢丝的正中央。钢丝很长，可以看作是无限长。节目主持人会给该跳蚤发一张卡片。卡片上写有N+1个自然数。其中最后一个是M，而前N个数都不超过M，卡片上允许有相同的数字。(Z city is home to many flea. There is an entertainment program in the city of Z Saturday life channel. Right in the middle of a flea would be invited on a high wire. The wire is very long, can be regarded as infinite. The host will send a card to the flea. Write on the cards with natural number N+1. The last one is M, and the N number is less than M, the same numbers are allowed on the card.)