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

import sys

class Scanner:

    def __init__(self):
        self.current_tokens = []

    def remaining_tokens(self):
        return len(self.current_tokens)

    def nextline(self):
        assert self.remaining_tokens() == 0, "Reading next line with remaining tokens"
        return input()

    def nexttokens(self):
        return self.nextline().split()
    
    def nexttoken(self):
        if len(self.current_tokens) == 0:
            self.current_tokens = self.nexttokens()
        assert self.remaining_tokens() > 0, "Not enough tokens to parse."
        return self.current_tokens.pop(0)

    def nextints(self, n=-1):
        if n == -1:
            return list(map(int, self.nexttokens()))
        else:
            return (self.nextint() for i in range(n))
    
    def nextint(self):
        return int(self.nexttoken())

def quit():
    sys.exit(0)

stdin = Scanner()
nextint = stdin.nextint
nextints = stdin.nextints
nextline = stdin.nextline

a, b = nextints(2)

h = 0
while a > 0:
    h += 1
    a -= 1

    if h % b == 0:
        a += 1

print(h)
