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: Accepted)

var toInt = x=>parseInt(x,10);
var toIntArr = arr=>arr.map(x=>toInt(x));
var abs = x=>x>0?x:-x;
function min(){var rest=arguments,v=rest[0];for(var i=1;i<rest.length;i++)if(rest[i]<v)v=rest[i];return v}
function max(){var rest=arguments,v=rest[0];for(var i=1;i<rest.length;i++)if(rest[i]>v)v=rest[i];return v}
function gcd(){var rest=arguments,v=rest[0],temp=(a,b)=>b?temp(b,a%b):a;for(var i=1;i<rest.length;i++)v=temp(v,rest[i]);return v}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));
 
function Main(input){
	var input = input.split('\n');
	var n = toInt(input[0]);
	var vs = toIntArr(input[1].split(' '));
	var odd = [];
	var even = [];
	for(var i = 0; i < n; i++){
		if(i%2===1){
			even[vs[i]] = !even[vs[i]]? 1: even[vs[i]] + 1; 
		}else{
			odd[vs[i]] = !odd[vs[i]]? 1: odd[vs[i]] + 1; 
		}
	}
	var xs = odd.map((e,ind,arr)=>({el:e,ind:ind})).filter(el=>el.el>0).sort((a,b)=>b.el-a.el);
	var ys = even.map((e,ind,arr)=>({el:e,ind:ind})).filter(el=>el.el>0).sort((a,b)=>b.el-a.el);
	var ans = 0;
	if(xs[0].ind === ys[0].ind){
		if(xs.length === 1){
			if(ys.length === 1){
				ans = n/2;
			}else{
				ans = n/2 - ys[1].el;
			}
		}else{
			if(ys.length === 1){
				ans = n/2 - xs[1].el;
			}else{
				ans = min(n - xs[0].el - ys[1].el, n - xs[1].el - ys[0].el);
			}
		}
	}else{
		ans = n - xs[0].el - ys[0].el;
	}

	console.log(ans);
	return 0;
}