Iroha Loves Strings (ABC Edition)

AtCoder

IDabc042_b

Time2000ms

Memory256MB

Difficulty—

Iroha has a sequence of $N$ strings $S_1, S_2, ..., S_N$. The length of each string is $L$. She will concatenate all of the strings in some order, to produce a long string. Among all strings that she can produce in this way, find the lexicographically smallest one. Here, a string $s=s_1s_2s_3$...$s_n$ is _lexicographically smaller_ than another string $t=t_1t_2t_3$...$t_m$ if and only if one of the following holds: * There exists an index $i(1≦i≦min(n,m))$, such that $s_j = t_j$ for all indices $j(1≦j<i)$, and $s_i<t_i$. * $s_i = t_i$ for all integers $i(1≦i≦min(n,m))$, and $n<m$. ## Constraints * $1 ≦ N, L ≦ 100$ * For each $i$, the length of $S_i$ equals $L$. * For each $i$, $S_i$ consists of lowercase letters. ## Input The input is given from Standard Input in the following format: $N$ $L$ $S_1$ $S_2$ : $S_N$ [samples]

Samples

Input #1

3 3
dxx
axx
cxx

Output #1

axxcxxdxx

The following order should be used: `axx`, `cxx`, `dxx`.

API Response (JSON)

{
  "problem": {
    "name": "Iroha Loves Strings (ABC Edition)",
    "description": {
      "content": "Iroha has a sequence of $N$ strings $S_1, S_2, ..., S_N$. The length of each string is $L$. She will concatenate all of the strings in some order, to produce a long string. Among all strings that she ",
      "description_type": "Markdown"
    },
    "platform": "AtCoder",
    "limit": {
      "time_limit": 2000,
      "memory_limit": 262144
    },
    "difficulty": "None",
    "is_remote": true,
    "is_sync": true,
    "sync_url": null,
    "sign": "abc042_b"
  },
  "statements": [
    {
      "statement_type": "Markdown",
      "content": "Iroha has a sequence of $N$ strings $S_1, S_2, ..., S_N$. The length of each string is $L$.\nShe will concatenate all of the strings in some order, to produce a long string.\nAmong all strings that she ...",
      "is_translate": false,
      "language": "English"
    }
  ]
}

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