Introduction - If you have any usage issues, please Google them yourself
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.