R49

#include<bits/stdc++.h>
using namespace std;
int32_t main()
{
     int T; cin>>T;
     while(T--)
     {
         int n; cin>>n;
         string ss; cin>>ss;
         int t=1;
         for(int i=0;i<n/2;i++)
         {
             if(ss[i]-ss[n-1-i]==0||fabs(ss[i]-ss[n-1-i])==2)
                continue;
             else t=0;
         }
          if(t==0) cout<<"NO"<<endl;
          else cout<<"YES"<<endl;
     }
}

#include<bits/stdc++.h>
#define int long long
#define MAX(a,b,c) max(a,max(b,c))
#define MIN(a,b,c) min(a,min(b,c))
#define pb push_back
#define fi first
#define se second
typedef long long ll;
typedef long long LL;
typedef unsigned long long ull;
typedef unsigned long long uLL;
using namespace std;
const int maxn=1e5+10;
const int INF=0x3f3f3f3f;
int32_t main()
{
     int n,q; cin>>n>>q;
     if(n%2==0)
     {
         int ans1=0;
         int ans2=n*n/2;
         while(q--)
         {
             int a,b;cin>>a>>b;
             if( (a+b)%2==0 ) cout<<ans1+(a-1)*n/2+(b+1)/2<<endl;
             else   cout<<ans2+(a-1)*n/2+(b+1)/2<<endl;
         }
     }
     else if(n%2==1)
     {
         int ans1=0;
         int ans2=n*n/2+1;
         while(q--)
         {
             int a,b;cin>>a>>b;
             if( (a+b)%2==0 )
             {
                 if(a%2==1) cout<<(a-1)/2*n+(b+1)/2<<endl;
                 else if(a%2==0) cout<<(a-2)/2*n+(n+1)/2+(b+1)/2<<endl;
             }
             else
             {
                 if(a%2==1) cout<<ans2+(a-1)/2*n+(b+1)/2<<endl;
                 else if(a%2==0) cout<<ans2+(a-2)/2*n+(n-1)/2+(b+1)/2<<endl;
             }
         }
     }
}