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: Time Limit Exceeded)

n = int(input())
vs = list(map(int, input().split()))

vs1 = [vs[i] for i in range(n) if i % 2 == 0]
vs2 = [vs[i] for i in range(n) if i % 2 != 0]

vsc1 = []
for v in set(vs1):
    vsc1.append((v, vs1.count(v)))

vsc2 = []
for v in set(vs2):
    vsc2.append((v, vs2.count(v)))

vsc1 = sorted(vsc1, key=lambda x: x[1], reverse=True)
vsc2 = sorted(vsc2, key=lambda x: x[1], reverse=True)
vsc1.append((-1, 0))
vsc2.append((-1, 0))

if vsc1[0][0] != vsc2[0][0]:
    print(n - (vsc1[0][1] + vsc2[0][1]))
else:
    print(n - max(vsc1[0][1] + vsc2[1][1], vsc1[1][1] + vsc2[0][1]))