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 C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <iostream>

using namespace std;

int f0[100005], f1[100005];

int main()
{
    int n, a0=0, a1=0, x;
    cin>>n;
    int v[n];
    for(int i=0; i<n; i++){
        cin>>v[i];
        if(i%2==0)
            f0[v[i]]++;
        else
            f1[v[i]]++;
    }

    for(int i=0; i<100005; i++){
        if(f0[i]>a0){
            a0=f0[i];
            x=i;
        }
    }

    for(int i=0; i<100005; i++){
        if(i==x)
            continue;
        else
            if(f1[i]>a1)
                a1=f1[i];
    }
    cout<<n-a0-a1;


    return 0;
}