Minimised Operations- ICL2023

#include <iostream>
using namespace std;
#include<bits/stdc++.h>
int main() {
	// your code goes here
	int t;
	cin>>t;
	while(t--)
	{
	    int n;
	    cin>>n;
	    string input;cin>>input;
	    int ans=1e9;
	    for(int j=0;j<26;j++)
	    {
	        int curAns=0;
	        for(int i=0;i<n;i++)
    	    {
    	        if(input[i]-'a'!=((j+i)%26))curAns++;
    	    }
    	    ans=min(ans,curAns);
	    }
	    cout<<ans<<endl;

	}
}