Last week,Radical gave you a problem , but only one guy solved it.He's very down,so today he prepares a simple problem for you.
We all known arrays.And now I want to tell you a K-Periodic array whose length is divisible by k.
For example,array[2,1,2,1,2,1]is at the same time 2-periodic and 6-periodic.
For the given array,consisits of numbers one and two,find the minimum numbers of elements to change to make the array
K-Periodic.If the array already is k-periodic, then the required value equals 0.

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 n is
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.

Print the minimum number of the array elements we need to change to make the array K-Periodic.