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

count = 0
remainder = 0

(a,b)=map(int,raw_input().split())

candles = a
while candles > 0:
	count = count + candles
#	print 'We have %d candles. Count is now %d' % (candles,count)
	remainder = remainder + candles % b
#	print 'We have %d stubs added to get %d stubs' % (candles % b,remainder)
	candles = candles // b

#print '\n\nWe now take care of %d remaining stubs.'%(remainder)
while remainder > b-1:
	#print 'From %d stubs, we create %d candles and %d stubs are left.' % (remainder,remainder//b,remainder-b * remainder//b)
	candles = remainder//b
	count = count + candles

	remainder = remainder - b * candles
	
	
	remainder = remainder + candles
	#print 'Count is now %d and we have %d stubs now' % (count,remainder)

print count