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

var input = readline().split(" "), a = +input[0], b = +input[1], hours = 0, rest = 0;

for(i = 0; a > 0 ;i++){
	hours += a;
	rest += (a/b > 1) ? a%b : 0;
	a = Math.floor(a/b) + Math.floor(rest/b);
	if(rest/b >= 1){
		rest -= Math.floor(rest/b)*b;
	}
}
write(hours);