Touitsu

AtCoder

IDnikkei2019_qual_b

Time2000ms

Memory256MB

Difficulty—

You are given three strings $A, B$ and $C$. Each of these is a string of length $N$ consisting of lowercase English letters. Our objective is to make all these three strings equal. For that, you can repeatedly perform the following operation: * Operation: Choose one of the strings $A, B$ and $C$, and specify an integer $i$ between $1$ and $N$ (inclusive). Change the $i$\-th character from the beginning of the chosen string to some other lowercase English letter. What is the minimum number of operations required to achieve the objective? ## Constraints * $1 \leq N \leq 100$ * Each of the strings $A, B$ and $C$ is a string of length $N$. * Each character in each of the strings $A, B$ and $C$ is a lowercase English letter. ## Input Input is given from Standard Input in the following format: $N$ $A$ $B$ $C$ [samples]

Samples

Input #1

4
west
east
wait

Output #1

3

In this sample, initially $A =$ `west`、$B =$ `east`、$C =$ `wait`. We can achieve the objective in the minimum number of operations by performing three operations as follows:

*   Change the second character in $A$ to `a`. $A$ is now `wast`.
*   Change the first character in $B$ to `w`. $B$ is now `wast`.
*   Change the third character in $C$ to `s`. $C$ is now `wast`.

Input #2

9
different
different
different

Output #2

0

If $A, B$ and $C$ are already equal in the beginning, the number of operations required is $0$.

Input #3

7
zenkoku
touitsu
program

Output #3

API Response (JSON)

{
  "problem": {
    "name": "Touitsu",
    "description": {
      "content": "You are given three strings $A, B$ and $C$. Each of these is a string of length $N$ consisting of lowercase English letters. Our objective is to make all these three strings equal. For that, you can r",
      "description_type": "Markdown"
    },
    "platform": "AtCoder",
    "limit": {
      "time_limit": 2000,
      "memory_limit": 262144
    },
    "difficulty": "None",
    "is_remote": true,
    "is_sync": true,
    "sync_url": null,
    "sign": "nikkei2019_qual_b"
  },
  "statements": [
    {
      "statement_type": "Markdown",
      "content": "You are given three strings $A, B$ and $C$. Each of these is a string of length $N$ consisting of lowercase English letters.\nOur objective is to make all these three strings equal. For that, you can r...",
      "is_translate": false,
      "language": "English"
    }
  ]
}

Full JSON Raw Segments