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)

def main():
    n=int(input())
    v=list(map(int,input().split()))
    l1=[0]*(10**5+1)
    l2=[0]*(10**5+1)
    for i,vn in enumerate(v):
        if i%2==0:
            l1[vn]+=1
        else:
            l2[vn]+=1
    f1,f2,s1,s2=0,0,0,0
    for i,ln in enumerate(l1):
        s1=max(s1,min(ln,f1))
        f1=max(f1,ln)
    for i,ln in enumerate(l2):
        s2=max(s2,min(ln,f2))
        f2=max(f2,ln)
    print(min(n-f1-s2,n-f2-s1))

if __name__ == '__main__':
    main()