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 Java (OpenJDK 11.0.6) (judge verdict: Wrong Answer)

import java.util.Map;
import java.util.Scanner;
import java.util.TreeMap;


	public class Main {
		
		public static void main(String[] args) {

			Scanner sc = new Scanner(System.in);
			
			int n = sc.nextInt();
			TreeMap<Integer,Integer> m1 = new TreeMap<Integer,Integer>();
			TreeMap<Integer,Integer> m2 = new TreeMap<Integer,Integer>();
			int sum1 = 0;
			int max1 = 0;
			int key1 = 0;
			
			int sum2 = 0;
			int max2 = 0;
			int key2 = 0;
			
			for(int i=0;i<n/2;i++) {
				m1.merge(sc.nextInt(), 1, Integer::sum);
				m2.merge(sc.nextInt(), 1, Integer::sum);
			}
			
			for(Map.Entry<Integer, Integer> e : m1.entrySet()) {
				sum1 += e.getValue();
				if(max1<=e.getValue()) {
					max1 = Math.max(max1, e.getValue());
					key1 = e.getKey();
				}
				
			}
			
			for(Map.Entry<Integer, Integer> e : m2.entrySet()) {
				sum2 += e.getValue();
				if(max2<=e.getValue()) {
					max2 = Math.max(max2, e.getValue());
					key2 = e.getKey();
				}
			}
			if(m1.equals(m2)) {
				System.out.println(n/2);
			}else {
				System.out.println(sum1+sum2-m1.get(key1)-m2.get(key2));
			}
			
			
	    }
		
	}