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 Python (3.4.3) (judge verdict: Accepted)

from collections import Counter
 
n = int(input())
V =list(map(int,input().split()))

V1 = V[::2]
V2 = V[1::2]
 
V1c = Counter(V1).most_common()
V2c = Counter(V2).most_common()

k1, v1 = V1c[0][0], V1c[0][1]
k2, v2 = V2c[0][0], V2c[0][1]

ans = 0
if k1 == k2:
    ans = n - v1
    m = 0
    if len(V1c) >= 2:
        m = max(m, V1c[1][1])
    if len(V2c) >= 2:
        m = max(m, V2c[1][1])
    ans = ans - m
else:
    ans = n - v1 - v2
print(ans)