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)

var lines = [];

var readline = require('readline');
var rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout,
})

rl.on('line', function (x) {
    lines.push(x);
});

rl.on("close", function () {
    var N = Number(lines[0]);
    var V = lines[1].split(" ").map(i => Number(i));

    var even = {}; var odd = {}; var ans = 0;

    for (var i = 0; i < N; i++) {
        if (i % 2 === 0) { even[V[i]] === undefined ? even[V[i]] = 1 : even[V[i]]++ }
        else { odd[V[i]] === undefined ? odd[V[i]] = 1 : odd[V[i]]++ }
    }

    if (Object.keys(even).length === 1 && Object.keys(odd).length === 1 && V[0] === V[1]) { console.log(even[V[0]]) }
    else {
        var max = 0;
        if (Object.keys(even).length !== 1) {
            Object.keys(even).forEach((value) => {
                if (even[value] < max) { ans += even[value] }
                else { ans += max; max = even[value]; }
            })
        }

        var max = 0;
        if (Object.keys(odd).length !== 1) {
            Object.keys(odd).forEach((value) => {
                if (odd[value] < max) { ans += odd[value] }
                else { ans += max; max = odd[value]; }
            })
        }
        console.log(ans)
    }
});