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

def seperateints(x):  
    k=''
    l=[]
    for i in x :
        if i==' ' :
            l.append(int(k))
            k=''
            continue 
        k=k+i
    l.append(int(k))   
    return(l)
def luckynum(x):
    for i in x : 
        if i!='4' and i!='7' :
            return False
    return True 
l=seperateints(input())
n=l[0]
while l[0]>l[1] :
    if l[0]%l[1]==0:
         l[0]=l[0]//l[1]
         x=l[0]
    else :
        x=l[0]//l[1]+1
        l[0]=l[0]//l[1]
    n=n+x
    if l[0]<l[1]:
        break
print(n)    