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 (3.8.2) (judge verdict: Accepted)

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

odd={}
even={}
total={}

for i in range(n):
    t=a[i]
    if i%2==0:
        if t in odd:
            odd[t]+=1
        else:
            odd[t]=1
    else:
        if t in even:
            even[t]+=1
        else:
            even[t]=1
    if t in total:
        total[t]+=1
    else:
        total[t]=1

l=len(odd)+len(even)

odd=sorted(odd.items(),key=lambda x: x[1],reverse=True)
even=sorted(even.items(),key=lambda x: x[1],reverse=True)
total=sorted(total.items(),key=lambda x: x[1],reverse=True)

ans=0

if len(total)==1:
    print(n//2)
    exit(0)

ans=n
cnt1=0
for i in odd:
    if cnt1==2:
        break
    cnt2=0
    for j in even:
        if cnt2==2 or i[0]==j[0]:
            continue
    
        ans=min(ans,n-i[1]-j[1])
        cnt2+=1
    cnt1+=1

print(ans)