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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.Arrays;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		int N = in.nextInt();
		int[][] l = new int[100001][2];
		int[][] r = new int[100001][2];
		for (int i = 0; i < N / 2; i++) {
			int a = in.nextInt();
			int b = in.nextInt();
			l[a][0] = a;
			l[a][1]++;
			r[b][0] = b;
			r[b][1]++;
		}
		Arrays.sort(l, (x, y) -> Integer.compare(x[1], y[1]));
		Arrays.sort(r, (x, y) -> Integer.compare(x[1], y[1]));
		if (l[l.length - 1][0] != r[r.length - 1][0]) {
			System.out.println(N - l[l.length - 1][1] - r[r.length - 1][1]);
		} else {
			System.out.println(
					Math.min(N - l[l.length - 2][1] - r[r.length - 1][1], N - l[l.length - 1][1] - r[r.length - 2][1]));
		}
		in.close();
	}
}