#include <bits/stdc++.h>   using namespace std;   int mod = 1e9 + 7;   int mat[2 * 100001][26];   int n, k;   int count3 = 0;   void find_most(int x, int y) {     int total = 0, mx = 0;     for (int i = 0; i < 26; i++) {       total += mat[x][i] + mat[y][i];       mx = max(mx, mat[x][i] + mat[y][i]);     }     count3 += total - mx;   }   int main() {     ios_base::sync_with_stdio(0);     cin.tie(0);     int t;     cin >> t;     while (t--) {       cin >> n >> k;       string s;       cin >> s;       for (int i = 0; i < k; i++) {         for (int j = 0; j < 26; j++) mat[i][j] = 0;       }       for (int i = 0; i < n; i++) {         mat[i % k][s[i] -  a ]++;       }       for (int i = 0; i < k; i++) {         find_most(i, k - i - 1);       }       cout << (count3) / 2;       count3 = 0;       cout <<   n ;     }     return 0;   }   