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)

n = int(input())
v = list(map(int,input().split()))
v1 = []
v2 = []
for i in range(n):
    if i%2 == 0:
        v1.append(v[i])
    else:
        v2.append(v[i])

sv1 = set(v1)
sv2 = set(v2)
if len(sv1) == 1 and len(sv2) == 1 :
    if sv1 != sv2:
        print(0)
    else:
        print(n//2)
else:
    dic1 = { i : 0 for i in sv1}
    dic2 = { i : 0 for i in sv2}
    for i in v1:
        dic1[i] = dic1[i] + 1
    for i in v2:
        dic2[i] = dic2[i] + 1
    #print(dic1, dic2)
    dic1 = sorted(dic1.items(), key=lambda x: -x[1])
    dic2 = sorted(dic2.items(), key=lambda x: -x[1])
    if dic1[0][0] != dic2[0][0]:
        print(n-(dic1[0][1]+dic2[0][0]))
    else:
        if len(dic1)==1:
            print(n- (dic1[0][1]+dic2[1][1]))
        elif len(dic2)==1:
            print(n- (dic1[1][1]+dic2[0][1]))
        elif dic1[1][1]+dic2[0][1] >= dic1[0][1]+dic2[1][1] :
            print(n- (dic1[1][1]+dic2[0][1]))
        else :
            print(n- (dic1[0][1]+dic2[1][1]))