/* Problem URL: https://codeforces.com/problemset/problem/1974/D */

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

template <class T, class comp = less<>>
using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;

#define V vector

#define rmin(a, b) a = min(a, b)
#define rmax(a, b) a = max(a, b)

#define rep(i, lim) for (int i = 0; i < (lim); i++)
#define nrep(i, s, lim) for (int i = s; i < (lim); i++)

#define repv(i, v) for (auto &i : (v))
#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
#define sortv(v) sort(v.begin(), v.end())
#define all(v) (v).begin(), (v).end()

using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vvvvi = vector<vvvi>;

using ll = long long;

using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vvvvl = vector<vvvl>;

template<class v>
auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
    os << vec[0];
    for (size_t i = 1; i < vec.size(); i++) {
        os << ' ' << vec[i];
    }
    os << '\n';
    return os;
}

template<class v>
auto operator>>(istream &is, vector<v> &vec)->istream& {
    for (auto &i : vec) {
        is >> i;
    }
    return is;
}

template<class v>
auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
    for (auto &i : vec) {
        os << i[0];
        for (size_t j = 1; j < i.size(); j++) {
            os << ' ' << i[j];
        }
        os << '\n';
    }
    return os;
}

template<class v>
auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
    for (auto &i : vec) {
        for (auto &j : i) {
            is >> j;
        }
    }
    return is;
}

const int oo = INT32_MAX >> 1;
const ll OO = INT64_MAX >> 1;


void pre()
{

}

#define TEST 1

void solve()
{
    int n;
    cin >> n;
    string a;
    cin >> a;

    int x = 0;
    int y = 0;

    pair<int, int> var[256];
    var['N'] = {0, 1};
    var['S'] = {0, -1};
    var['E'] = {1, 0};
    var['W'] = {-1, 0};

    repv(i, a) {
        x += var[i].first;
        y += var[i].second;
    }

    if ((x & 1) || (y & 1)) {
        cout << "NO\n";
        return;
    }

    x >>= 1;
    y >>= 1;

    if (x == 0 && y == 0) {
        if (a.size() == 2) {
            cout << "NO\n";
            return;
        }

        int ind1 = find(all(a), 'N') - a.begin();
        int ind2 = find(all(a), 'S') - a.begin();
        if (ind1 == n || ind2 == n) {
            ind1 = find(all(a), 'E') - a.begin();
            ind2 = find(all(a), 'W') - a.begin();
        }

        rep(i, n) {
            if (i == ind1 || i == ind2) {
                cout << 'H';
                continue;
            }

            cout << "R";
        }
        cout << '\n';
        return;
    }

    repv(i, a) {
        if (i == 'N' && y > 0) {
            y--;
            cout << "R";
            continue;
        }

        if (i == 'S' && y < 0) {
            y++;
            cout << "R";
            continue;
        }

        if (i == 'E' && x > 0) {
            x--;
            cout << "R";
            continue;
        }

        if (i == 'W' && x < 0) {
            x++;
            cout << "R";
            continue;
        }

        cout << "H";
    }
    cout << '\n';
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    pre();

    int t;
    (TEST && cin >> t) || (t = 1);
    while (t--) {
        solve();
    }
}