Asif and Game Show

Asif is participating in a Tv game show “hojoborolo” ( হযবরল ) । Where as a winner of every show participate can take money as many as they want but there is a simple restriction to do so . In the end part of the show , the presenter writes a number of N digits in a board. The participant must then erase exactly M digits from the number in the board; the number formed by the remaining digits is th