#include<bits/stdc++.h>
using namespace std;
#define IOS ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);


using ll = long long;
#define int ll
#define endl "\n"
#define no cout << "NO" << endl
#define yes cout << "YES" << endl
#define pb push_back
#define mkp make_pair
#define fi first
#define se second
#define ary(i) array<ll,(i)>
#define all(x) x.begin(),x.end()
const int maxn=2e5+7;
const int inf=1e9+7;
const int mod=998244353;



void solve(){
  int ans=0;
  string mr;
  cin>>mr;
  int n=mr.size();
  for(int i=0;i<n;i++){
      if(mr[i]!=mr[n-i-1]){
          ans++;
      }
  }
  ans/=2;
    cout<<ans<<endl;
}

#undef int



int main()
{
    //    IOS
    int n;
    cin>>n;
//    n=1;
    while(n--){
        solve();
    }


}