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

class NewYearCandles:
    def solve(self, a, b):
        candlecount = a
        unused = a
        used = 0
        hourcount = 0
        while True:
            while unused > 0:
                hourcount+=1
                used+=1
                unused -= 1
            unused+=int(used/b)
            used-=(int(used/b) * b)
            if unused==0: break
        return hourcount

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