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: Runtime Error)

#include <bits/stdc++.h>
using namespace std;

int main()
{
    long n;
    cin >> n;
    static vector<int>a(n>>1),b(n>>1);
    for (int x,i = 0; i < n>>1; i++)
    {
        cin >> x;
        a[x]++;
        cin >> x;
        b[x]++;
    }
    long maxA = *max_element(a.begin(),a.end()), 
         maxB = *max_element(b.begin(),b.end());
    if (maxA != maxB)
        cout << n-(maxA + maxB);
    else
    {
        a[max_element(a.begin(),a.end())-a.begin()] = -1;
        b[max_element(b.begin(),b.end())-b.begin()] = -1;
        long MaxA = *max_element(a.begin(),a.end()), 
             MaxB = *max_element(b.begin(),b.end());
        cout << min(n-MaxA-maxB, n - maxA-MaxB);
    }
    return 0;
}