5 3
 1000 3
 777 17
 4 3
 2 2
 100 4
 10 4
 999 2
 6 4
 1 2
 17 3
 1 4
 26 8
 91 5
 1 3
 1000 2
 20 3
 9 4
 123 5
 1000 1000
 3 2
 3 3
 80 970
 1000 4
 1 1000

7
 1499
 825
 5
 3
 133
 13
 1997
 7
 1
 25
 1
 29
 113
 1
 1999
 29
 11
 153
 1001
 5
 4
 80
 1333
 1

a,b = list(map(int,input().split()));

burnt = a;
partially_burnt = 0;
hours = a;

while ( burnt > b - 1 ):

#	temp = partially_burnt;
	partially_burnt = (burnt%b) ;
	hours += burnt//b;
	#print ( "burnt" + " " + str(burnt) )  ;
	#print ( "partially_burnt" + " " + str(partially_burnt) );
	burnt = burnt//b + partially_burnt;
	#partially_burnt = partially_burnt%b;
	

print ( int(hours) );
