A. K-Periodic Array

time limit per test

1 second

memory limit per test

256 megabytes

input

standard input

output

standard output

This task will exclusively concentrate only on the arrays where all elements equal 1 and/or 2.

Array a is k-period if its length is divisible by k and there is such array b of length k, that a is represented by array b written exactly  times consecutively. In other words, array a is k-periodic, if it has period of length k.

For example, any array is n-periodic, where n is the array length. Array [2, 1, 2, 1, 2, 1] is at the same time 2-periodic and 6-periodic and array [1, 2, 1, 1, 2, 1, 1, 2, 1] is at the same time 3-periodic and 9-periodic.

For the given array a, consisting only of numbers one and two, find the minimum number of elements to change to make the array k-periodic. If the array already is k-periodic, then the required value equals 0.

Input

The first line of the input contains a pair of integers n, k (1 ≤ k ≤ n ≤ 100), where n is the length of the array and the value nis divisible by k. The second line contains the sequence of elements of the given array a1, a2, ..., an (1 ≤ ai ≤ 2), ai is the i-th element of the array.

Output

Print the minimum number of array elements we need to change to make the array k-periodic. If the array already is k-periodic, then print 0.

Sample test(s)

input

6 2
2 1 2 2 2 1

output

1

input

8 4
1 1 2 1 1 1 2 1

output

0

input

9 3
2 1 1 1 2 1 1 1 2

output

3

Note

In the first sample it is enough to change the fourth element from 2 to 1, then the array changes to [2, 1, 2, 1, 2, 1].

In the second sample, the given array already is 4-periodic.

In the third sample it is enough to replace each occurrence of number two by number one. In this case the array will look as[1, 1, 1, 1, 1, 1, 1, 1, 1] — this array is simultaneously 1-, 3- and 9-periodic.

解题说明：此题要求的是改变最小的数字让数列满足k次循环。由于数列中只有1和2，可以统计出循环中k个对应位置上1和2的个数之和，然后遍历这k个位置，每一个位置选择一个较小值进行调整，只需要调整这些对应位置让其满足k次循环即可。

#include
#include
#include
#include
#include
#include
using namespace std;

int main()
{
	int n,k,i,j,ans,x;
	scanf("%d%d",&n,&k);
	int a[101][3],q=0;
	memset(a,0,sizeof(a));
	while(n--)
	{
		scanf("%d",&x);
		if(x==1)
		{
			a[q][1]++;
		}
		if(x==2)
		{
			a[q][2]++;
		}
		q++;
		q=q%k;
	}
	ans=0;
	for(i=0;i