1 #include <cstdio>
2 #include <cstring>
3 #include <algorithm>
4 using namespace std;
5
6 const int maxn = 1000 + 10;
7 const int maxm = 30;
8
9 int n, k;
10
11 char s[maxn];
12 int d[maxn][maxm];
13
14 int cnt[maxn];
15 bool vis[maxn][maxm];
16
17 int main()
18 {
19 int T; scanf("%d", &T);
20 while(T--)
21 {
22 scanf("%d %s", &k, s);
23 n = strlen(s);
24
25 memset(d, 0x3f, sizeof(d));
26 memset(cnt, 0, sizeof(cnt));
27 memset(vis, false, sizeof(vis));
28 for(int i = 0; i < n; i += k)
29 {
30 for(int j = 0; j < k; j++)
31 {
32 int ch = s[i + j] - 'a';
33 if(!vis[i][ch]) cnt[i]++;
34 vis[i][ch] = true;
35 }
36 }
37
38 for(int i = 0; i < 26; i++) if(vis[0][i]) d[0][i] = cnt[0];
39
40 for(int i = k; i < n; i += k)
41 for(int j = 0; j < 26; j++) if(vis[i][j])
42 for(int t = 0; t < 26; t++) if(vis[i - k][t])
43 {
44 if(vis[i][t] && (j != t || cnt[i] == 1))
45 d[i][j] = min(d[i][j], d[i-k][t] + cnt[i] - 1);
46 else
47 d[i][j] = min(d[i][j], d[i-k][t] + cnt[i]);
48 }
49
50 int ans = n;
51 for(int i = 0; i < 26; i++) ans = min(ans, d[n - k][i]);
52 printf("%d\n", ans);
53 }
54
55 return 0;
56 }
