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: Wrong Answer)

#!/usr/bin/env python3
import collections
N = int(input())
V = list(map(int, input().split()))

V1 = V[::2]
V2 = V[1::2]

if len(set(V1)) == 1 and len(set(V2)) == 1 and V1[0] == V2[0]:
    print(len(V1))
    exit()


C1 = collections.Counter(V1)
C2 = collections.Counter(V2)

max1 = 0
index1 = 0
max2 = 0
index2 = 0

for c, i in C1.items():
    if i > max1:
        max1 = i
        index1 = c

for c, i in C2.items():
    if i > max2:
        max2 = i
        index2 = c


nokori1 = len(V1) - max1
nokori2 = len(V2) - max2

ans = 0

if index1 == index2:
    ans = nokori1 + max1
else:
    ans = nokori1 + nokori2
print(ans)