#pragma GCC optimize(2)#include<iostream>#include<algorithm>#include<cmath>#include<cstring>#include<stack>#include<map>#include<queue>#include<cstdio>#include<set>#include<map>#include<string>usingnamespace std;constint maxn =1000+10;voidsolve(){int t;
cin >> t;while(t--){int n, k;
string s;
cin >> n >> k >> s;int ans =0;for(int i =0; i <(k &1? k /2+1: k /2); i++){int cnt[200]={0};for(int j =0; i + j * k < n; j++){
cnt[s[i + j * k]]++;if(i + j * k != k - i -1+ j * k)
cnt[s[k - i -1+ j * k]]++;}sort(cnt, cnt +200);if((k &1)&& i == k /2) ans += n / k - cnt[199];else ans +=2* n / k - cnt[199];}
cout << ans << endl;}}intmain(){//freopen("Testin.txt", "r", stdin);solve();return0;}