Narnal is a beggar, nevertheless, his daily income is stable. Nowadays he wants to buy \(M\) games online. The good news is that all the games he wants are on special sales promotion, in which the price of each game will decrease \(K\) units day by day as long as the price can maintain a positive price value (if the price is \(5\), each day decrease \(6\), then the price should maintain at \(5\)). The price of each game decreases on the morning of each day except the ﬁrst day. However, Narnal adds his income to his wallet on the evening of each day including the ﬁrst day.