Problem:
Score : 300 points

Problem Statement

A sequence a_1,a_2,... ,a_n is said to be /\/\/\/ when the following conditions are satisfied:

For each i = 1,2,..., n-2, a_i = a_{i+2}.

Exactly two different numbers appear in the sequence.

You are given a sequence v_1,v_2,...,v_n whose length is even.
We would like to make this sequence /\/\/\/ by replacing some of its elements.
Find the minimum number of elements that needs to be replaced.

Constraints

2 \leq n \leq 10^5

n is even.

1 \leq v_i \leq 10^5

v_i is an integer.

Input

Input is given from Standard Input in the following format:

n
v_1 v_2 ... v_n

Output

Print the minimum number of elements that needs to be replaced.

Sample Input 1

4
3 1 3 2

Sample Output 1

1

The sequence 3,1,3,2 is not /\/\/\/, but we can make it /\/\/\/ by replacing one of its elements: for example, replace the fourth element to make it 3,1,3,1.

Sample Input 2

6
105 119 105 119 105 119

Sample Output 2

0

The sequence 105,119,105,119,105,119 is /\/\/\/.

Sample Input 3

4
1 1 1 1

Sample Output 3

2

The elements of the sequence 1,1,1,1 are all the same, so it is not /\/\/\/.

Solution in JavaScript (node.js v5.12) (judge verdict: Wrong Answer)

// inputに入力データ全体が入る
function Main(input) {
  inp = input.split('\n');
  var N = Number(inp[0]);
  var an = inp[1].split(' ');
  an.map(e => Number(e));

  function chkArray(lt){
    var buf = '';
    for (var i = 0; i < lt.length; i++) {
      if (i === 0) buf = an[0];
      if (buf !== lt[i]) {
        return true;
      }
    }
    return false;
  }
  // 配列チェック
  if (chkArray(an) === false){
    console.log("%d", parseInt(an.length / 2, 10));
    return;
  }

  num1 = new Map(); // 配列要素偶数
  num2 = new Map(); // 配列要素奇数
  for (var i = 0; i < an.length; i++) {
    if (i % 2 === 0) {
      var val = num1.get(an[i]);
      if (!val) {
        val = 0;
        num1.set(an[i], val);
      }
      val++;
      num1.set(an[i], val);
    } else {
      var val = num2.get(an[i]);
      if (!val) {
        val = 0;
        num2.set(an[i], val);
      }
      val++;
      num2.set(an[i], val);
    }
  }

  // console.log(num1);
  // console.log(num2);
  function getCnt(numarray) {
    var array = [];
    var cnt = 0;
    for (var tmp of numarray) {
      array.push(tmp[1]); // 連想配列の値を取る
    }
    if (array.length >= 2) {
      array.sort((a, b) => b - a); // 降順ソート
      for (var i = 1; i < array.length; i++) {
        cnt += array[i];
      }
    } else if (array.length <= 1) {
      cnt = 0;
    }
    return cnt;
  }

  var ans = getCnt(num1);
  ans += getCnt(num2);

  console.log("%d", ans);



}
//*この行以降は編集しないでください（標準入出力から一度に読み込み、Mainを呼び出します）
Main(require("fs").readFileSync("/dev/stdin", "utf8"));