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

__author__ = 'Devesh Bajpai'

'''
https://codeforces.com/problemset/problem/379/A

Solution: a candles would burn for a hours. After that, we have a burnt candles, and we can take sets of b candles and
build one candle. In other words, we can build a/b candles from it. And we keep progressing till we have non zero candles
left to burn. 
'''


def solve(a, b):

    hours = 0

    while a > 0:
        hours += a
        a /= b

    return hours


if __name__ == "__main__":
    a, b = map(int, raw_input().split(" "))
    print solve(a, b)
