Problem:
Score : 700 points

Problem Statement

N problems are proposed for an upcoming contest. Problem i has an initial integer score of A_i points.

M judges are about to vote for problems they like. Each judge will choose exactly V problems, independently from the other judges,
and increase the score of each chosen problem by 1.

After all M judges cast their vote, the problems will be sorted in non-increasing order of score, and the first P problems will be chosen for the problemset.
Problems with the same score can be ordered arbitrarily, this order is decided by the chief judge.

How many problems out of the given N have a chance to be chosen for the problemset?

Constraints

2 \le N \le 10^5

1 \le M \le 10^9

1 \le V \le N - 1

1 \le P \le N - 1

0 \le A_i \le 10^9

Input

Input is given from Standard Input in the following format:

N M V P
A_1 A_2 ... A_N

Output

Print the number of problems that have a chance to be chosen for the problemset.

Sample Input 1

6 1 2 2
2 1 1 3 0 2

Sample Output 1

5

If the only judge votes for problems 2 and 5, the scores will be 2 2 1 3 1 2.
The problemset will consist of problem 4 and one of problems 1, 2, or 6.

If the only judge votes for problems 3 and 4, the scores will be 2 1 2 4 0 2.
The problemset will consist of problem 4 and one of problems 1, 3, or 6.

Thus, problems 1, 2, 3, 4, and 6 have a chance to be chosen for the problemset. On the contrary, there is no way for problem 5 to be chosen.

Sample Input 2

6 1 5 2
2 1 1 3 0 2

Sample Output 2

3

Only problems 1, 4, and 6 have a chance to be chosen.

Sample Input 3

10 4 8 5
7 2 3 6 1 6 5 4 6 5

Sample Output 3

8

Solution in PyPy3 (2.4.0) (judge verdict: Wrong Answer)

# 入力が10**5とかになったときに100ms程度早い
import sys
read = sys.stdin.readline


def read_ints():
    return list(map(int, read().split()))


def read_a_int():
    return int(read())


def read_matrix(H):
    '''
    H is number of rows
    '''
    return [list(map(int, read().split())) for _ in range(H)]


def read_map(H):
    '''
    H is number of rows
    文字列で与えられた盤面を読み取る用
    '''
    return [read()[:-1] for _ in range(H)]


def read_col(H, n_cols):
    '''
    H is number of rows
    n_cols is number of cols

    A列、B列が与えられるようなとき
    '''
    ret = [[] for _ in range(n_cols)]
    for _ in range(H):
        tmp = list(map(int, read().split()))
        for col in range(n_cols):
            ret[col].append(tmp[col])

    return ret


from bisect import bisect_left, bisect_right
N, M, V, P = read_ints()
A = read_ints()
A.sort()
edge_idx = N - P
edge = A[-P]
# ここに処理を書けば終わりだ
# M人がちょうどV配ることによる副作用の扱いがわからん...
Mls = [M] * N
# print(A)
left_point = V * M
for i in range(edge_idx - 1, -1, -1):
    sa = edge - A[i]
    if sa > left_point:
        break
    # 代入処理
    sa = min(sa, M)
    left_point -= sa
    Mls[i] -= sa
    A[i] = edge

mina = 0
if left_point > 0:
    for i, m in enumerate(Mls):
        if m == 0:
            mina += 1
            continue
        else:
            left_point -= m * (N - i)
            if left_point < 0:
                break
            elif left_point == 0:
                mina += 1
                break
            else:
                mina += 1


# print(Mls)
# print(A)

lower_bound_idx = bisect_left(A, edge)
n_candi = edge_idx - lower_bound_idx
print(P + n_candi - mina)
# print(A)