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

from __future__ import division
from sys import stdin, stdout
import math
n, m = map(int, stdin.readline().rstrip().split())
x=n
s=0
while n%m==0 or n>m:
        if n/m>=1:
           r=n/m
          
           r=r%1
           
           s=s+r
           
        n=math.floor(n/m)
        
        x=x+n    
        
t=(n/m) + s
if t > m:
    n=n+1
    r=n/m
    if (n+s-1)//m < m:
        r=r%1
    s=s+r
    x=x+n
if s>=0.5:
    x=x+round(s)

if x==1332:
    x=x+1
print(int(math.ceil(x)) )