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

p=input().split()
a=int(p[0])
b=int(p[1])
sum1=a
y=0
i=1
while(True):
    x=a//b
    y=y+a%b
    sum1=sum1+x
    a=x
    if(a<b):
        s=y+a
        break
    i=i+1
sum2=0
q=0
i=1
while(True):
    w=s//b
    q=q+s%b
    sum2=sum2+w
    s=w
    if(s<b):
        n=q+s
        break
    i=i+1
print(sum1+sum2+n//b)
