atcoder#ARC075B. [ABC063D] Widespread

[ABC063D] Widespread

Score : 400400 points

Problem Statement

You are going out for a walk, when you suddenly encounter NN monsters. Each monster has a parameter called health, and the health of the ii-th monster is hih_i at the moment of encounter. A monster will vanish immediately when its health drops to 00 or below.

Fortunately, you are a skilled magician, capable of causing explosions that damage monsters. In one explosion, you can damage monsters as follows:

  • Select an alive monster, and cause an explosion centered at that monster. The health of the monster at the center of the explosion will decrease by AA, and the health of each of the other monsters will decrease by BB. Here, AA and BB are predetermined parameters, and A>BA > B holds.

At least how many explosions do you need to cause in order to vanish all the monsters?

Constraints

  • All input values are integers.
  • 1N1051 \leq N \leq 10^5
  • 1B<A1091 \leq B < A \leq 10^9
  • 1hi1091 \leq h_i \leq 10^9

Input

Input is given from Standard Input in the following format:

NN AA BB

h1h_1

h2h_2

::

hNh_N

Output

Print the minimum number of explosions that needs to be caused in order to vanish all the monsters.

4 5 3
8
7
4
2
2

You can vanish all the monsters in two explosion, as follows:

  • First, cause an explosion centered at the monster with 88 health. The healths of the four monsters become 33, 44, 11 and 1-1, respectively, and the last monster vanishes.
  • Second, cause an explosion centered at the monster with 44 health remaining. The healths of the three remaining monsters become 00, 1-1 and 2-2, respectively, and all the monsters are now vanished.
2 10 4
20
20
4

You need to cause two explosions centered at each monster, for a total of four.

5 2 1
900000000
900000000
1000000000
1000000000
1000000000
800000000