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#include "bits/stdc++.h"
using namespace std;

#ifdef LOCAL
#include "debug.h"
#else
#define debug(x...)
#endif

void solve() {
    int n;
    string s;
    cin >> n >> s;
    if (n & 1) {
        vector<int> cnteven(26), cntodd(26);
        for (int i = 0; i < n; i++) {
            if (i & 1) {
                cntodd[s[i] - 'a']++;
            } else {
                cnteven[s[i] - 'a']++;
            }
        }
        debug(cnteven);
        debug(cntodd);
        bool f = false;
        if ((n / 2) & 1) {
            for (int i = 0; i < 26; i++) {
                if (cnteven[i] & 1) {
                    cout << "NO\n";
                    return;
                }
                if (cntodd[i] & 1) {
                    if (f) {
                        cout << "NO\n";
                        return;
                    } else {
                        f = true;
                    }
                }
            }
        } else {
            for (int i = 0; i < 26; i++) {
                if (cntodd[i] & 1) {
                    cout << "NO\n";
                    return;
                }
                if (cnteven[i] & 1) {
                    if (f) {
                        cout << "NO\n";
                        return;
                    } else {
                        f = true;
                    }
                }
            }
        }
        if (f) {
            cout << "YES\n";
        } else {
            cout << "NO\n";
        }
    } else {
        vector<int> cnteven(26), cntodd(26);
        for (int i = 0; i < n; i++) {
            if (i & 1) {
                cntodd[s[i] - 'a']++;
            } else {
                cnteven[s[i] - 'a']++;
            }
        }
        for (int i = 0; i < 26; i++) {
            if (cntodd[i] != cnteven[i]) {
                cout << "NO\n";
                return;
            }
        }
        cout << "YES\n";
    }
}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(NULL);
    int tests = 1;
    cin >> tests;
    while (tests--) {
        solve();
    }
    return 0;
}