题目描述

You are given $N$ strings $S_1,\ldots,S_N$ consisting of digits.

Find the maximum possible value, when interpreted as a decimal integer (after removing extra leading zeros), of a string obtained by choosing exactly $K$ of these strings and concatenating them in any order of your choice.

Here, the value obtained by interpreting a string consisting entirely of the character 0 as a decimal integer after removing extra leading zeros is defined to be $0$.

输入格式

The input is given from Standard Input in the following format:

• $N$ $K$
• $S_1$
• $\vdots$
• $S_N$

输出格式

Output the answer.

数据范围

• $1 \leq K \leq N \leq 10^5$
• $S_i$ is a string of length between $1$ and $10$ (inclusive) consisting of digits.
• $N$ and $K$ are integers.

3 2
123
45
6

45123

There are six strings obtained by choosing two of 123, 45, 6 and concatenating them: 12345, 1236, 45123, 456, 6123, 645.

Among these, the maximum value when interpreted as a decimal integer is $45123$.

5 3
00000
00
1
0000
000

1000000000

9 9
0000000001
000000002
00000003
0000004
000005
00006
0007
008
09

90080007000060000050000004000000030000000020000000001

The answer must be output without extra leading zeros.

• 来源：AtCoder ABC 471 F