I found an interesting problem on https://codeforces.com/problemset/problem/509/B:
There are n piles of pebbles on the table, the i-th pile contains a_{i} pebbles. Your task is to paint each pebble using one of the k given colors so that for each color c and any two piles i and j the difference between the number of pebbles of color c in pile i and number of pebbles of color c in pile j is at most one.

In other words, let's say that b_{i}, c is the number of pebbles of color c in the i-th pile. Then for any 1 ≤ c ≤ k, 1 ≤ i, j ≤ n the following condition must be satisfied |b_{i}, c - b_{j}, c| ≤ 1. It isn't necessary to use all k colors: if color c hasn't been used in pile i, then b_{i}, c is considered to be zero.


-----Input-----

The first line of the input contains positive integers n and k (1 ≤ n, k ≤ 100), separated by a space — the number of piles and the number of colors respectively.

The second line contains n positive integers a_1, a_2, ..., a_{n} (1 ≤ a_{i} ≤ 100) denoting number of pebbles in each of the piles.


-----Output-----

If there is no way to paint the pebbles satisfying the given condition, output "NO" (without quotes) .

Otherwise in the first line output "YES" (without quotes). Then n lines should follow, the i-th of them should contain a_{i} space-separated integers. j-th (1 ≤ j ≤ a_{i}) of these integers should be equal to the color of the j-th pebble in the i-th pile. If there are several possible answers, you may output any of them.


-----Examples-----
Input
4 4
1 2 3 4

Output
YES
1
1 4
1 2 4
1 2 3 4

Input
5 2
3 2 4 1 3

Output
NO

Input
5 4
3 2 4 3 5

Output
YES
1 2 3
1 3
1 2 3 4
1 3 4
1 1 2 3 4

I tried it in Python, but could not do it. Can you solve it?
n, colors = map(int, input().split())
lens = list(map(int, input().split()))
q = [[] for i in range(n)]

def end():
    for i in range(n):
        if lens[i] != len(q[i]):
            return False
    return True

mi = min(lens)
for i in range(n):
    while len(q[i]) < min(lens[i], 1 + mi):
        q[i].append(1)

k = 1
while not end():
    k += 1
    for i in range(n):
        if len(q[i]) < lens[i]:
            q[i].append(k)

ma = max(map(max, q))
if ma <= colors:
    print('YES')
    for w in q:
        for i in w:
            print(i, end=' ')
        print()
else:
    print('NO')