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)

'use strict'

function main(arg) {
    let lines = arg.split("\n");
    let N = lines[0];
    let list = lines[1].split(" ").map(n=>parseInt(n));
    let diffs = 0;
    
    for(let i=0; i<N-2; i++) {
        if(i > 1 && list[i] !== list[i-1] && list[i] !== list[i-2]) {
            diffs++;
            list[i] = list[i-2];
        }
        if(list[i] !== list[i+2] || list[i] == list[i-1]) {
            diffs++;
        }
    }
    
    console.log(diffs);
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));