// LUOGU_RID: 98382671
#include<bits/stdc++.h>
#define pcc pair<char,char>
using namespace std;
const int MAXN=1e5+1;
char s[MAXN],t[MAXN];
inline void solve() {
	int n;
	scanf("%d%s%s",&n,s+1,t+1);
	map <pcc,int> cnt;
	for(int i=1,j=n;i<=n;++i,--j) ++cnt[make_pair(min(s[i],t[j]),max(s[i],t[j]))];
	bool eq=false;
	for(auto u:cnt) {
		if(u.second%2==0) continue;
		if(u.first.first==u.first.second&&!eq) eq=true;
		else {
			puts("NO");
			return ;
		}
	}
	puts((eq&&n%2!=0)||(!eq&&n%2==0)?"YES":"NO");
}
signed main() {
	int T;
	scanf("%d",&T);
	while(T--) solve();
	return 0;
}