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

#https://codeforces.com/problemset/problem/379/A
#done

from sys import stdin

# a number of candles
# b make a new candle

a, b = [int(c) for c in stdin.readline().split()]



def re(candle, burnt_candle,time):
    time = time + candle
    burnt_candle = burnt_candle + candle
    candle = burnt_candle // b
    burnt_candle = burnt_candle - candle * b
    if candle > 0:
        return re(candle, burnt_candle, time)
    else:
        return time


print(re(a, 0, 0))