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 <bits/stdc++.h>
#define ll long long
#define ull unsigned ll
#define ld long double
#define pll pair<ll, ll>
#define pii pair<int, int>
#define f first
#define se second
#define pb push_back
 
 
using namespace std;
 
 
const int N =  3e5 + 123;
const int MAXN = 2e5;
const ull inf = 1e18 + 7;



int n, a[N], c1[N], c2[N]; 

 
int main() {
    cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
        if (i % 2 == 1)
            c1[a[i]]++;
        else
            c2[a[i]]++;
    }
    int mx1 = 0, mx2 = 0;
    for (int i = 1; i <= n; i++) {
        if (i % 2 == 1)
            mx1 = max(mx1, c1[a[i]]);
        else
            mx2 = max(mx2, c2[a[i]]);
    }
    cout << n - mx1 - mx2;
}