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

k=0
a=[]
s=raw_input()
x=map(int,s.split())
b=x[1]
k+=x[0]
a.append(x[0]%b)
while(x[0]/b!=0):
    k+=x[0]/b
    x[0]=x[0]/b
    a.append(x[0]%b)
if sum(a)>=b:
    d=sum(a)/b
    k+=d
    if(d+sum(a)%b)>=b:
        e=((d+sum(a)%b)/b)
        c=((d+sum(a)%b)%b)
        k+=e
        if(e+c)>=b:
            k+=(e+c)/b
print k