#include
using namespace std;
int main()
{int n,l,i;
char d;
cin>>n;
while(n–)
{ cin>>l;
string s;
cin>>s;
for( i=0;i+1<l;i+=2)
{ d=s[i];
s[i]=s[i+1];
s[i+1]=d;
}
for(i=0;i<l;i++)
{ s[i]=(char)('z'-s[i]+'a') ;
}
cout<<s<<endl;}
return 0;}