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1 #include<cstdio>
2 #include<iostream>
3 #include<algorithm>
4 #include<cstring>
5 #include<cmath>
6 #include<queue>
7 using namespace std;
8 const int maxn=5001;
9 int n,m,t;
10 short dp[maxn][maxn];
11 char s[maxn];
12 int main()
13 {
14 int i,j,k;
15 #ifndef ONLINE_JUDGE
16 freopen("1.in","r",stdin);
17 #endif
18 scanf("%d",&t);
19 while(t--)
20 {
21 int len=0;
22 scanf("%d",&len);
23 scanf("%s",s);
24 for(i=0;i<len;i++) dp[i][i]=1;
25 for(k=1;k<len;k++)
26 {
27 for(i=0;i+k<=len;i++)
28 {
29 int j=k+i;
30 if(s[i]!=s[j]) dp[i][j]=dp[i+1][j-1];
31 else dp[i][j]=min(dp[i+1][j],dp[i][j-1])+1;
32 }
33 }
34 printf("%d\n",dp[0][len-1]);
35 }
36 return 0;
37 }