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)

line = require('fs')
  .readFileSync('/dev/stdin', 'utf8')
  .split('\n')

n = parseInt(line[0])
v = line[1].split(' ')

var odds = {}
var even = {}
for (var i = 0; i < v.length; i++) {
  di = i & 1 ? even : odds
  di[v[i]] = !di[v[i]] ? 1 : di[v[i]] + 1
}

var a = []
var b = []
for (var k in odds) a.push({ v: k, n: odds[k] })
for (var k in even) b.push({ v: k, n: even[k] })

a.sort((x, y) => y.n - x.n)
b.sort((x, y) => y.n - x.n)

va = a[0]
vb = b[0]
if (va.v === vb.v) {
  if (va.n > vb.n) vb = !b[1] ? { n: 0 } : b[1]
  else va = !a[1] ? { n: 0 } : a[1]
}

log = console.log
// log('n', n)
// log('v', v)
// log('sorted', a, b)
// log('select', va, vb)
log(n / 2 - va.n + n / 2 - vb.n)