#include<bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef long double ld;
#define all(v) v.begin(),v.end()
#define nl "\n"
#define FIO \
    ios_base::sync_with_stdio(false);\
    cin.tie(NULL);\
    cout.tie(NULL);

void solve()
{
    ll n;   cin>>n;
    n++;
    string a,b; cin>>a>>b;
    a='A'+a,b='A'+b;

    string c=a,d=b;
    for(ll i=1;i<n;i++) if(d[i]<c[i] && d[i]>c[i-1])    c[i]=d[i];

    if(is_sorted(all(c)))
    {
        cout<<"Yes"<<nl;
        return;
    }
    c=b,d=a;
    for(ll i=1;i<n;i++) if(d[i]<c[i] && d[i]>c[i-1])    c[i]=d[i];
    if(is_sorted(all(c)))
    {
        cout<<"Yes"<<nl;
        return;
    }
    cout<<"No"<<nl;
}

int32_t main()
{
    ll t=1;
    cin>>t;
    for(ll i=1;i<=t;i++)
    {
        // cout<<"Case "<<i<<": ";
        solve();
    }
}