#include<bits/stdc++.h>
using namespace std;
constexpr int Inf = 1000000010;
constexpr long long INF= 2000000000000000000;

template<typename T> inline bool chmax(T &a, T b) { if (a < b) { a = b; return true; } return false; }
template<typename T> inline bool chmin(T &a, T b) { if (a > b) { a = b; return true; } return false; }

template<typename T,typename U>
T modpow(T N, U P, T M = -1) {
    if(P < 0) return 0;
    T ret = 1;
    if(M != -1) ret %= M;
    while(P) {
        if(P & 1) {
            if(M == -1) ret *= N;
            else ret = ret * N % M;
        }
        P /= 2;
        if(M == -1) N *= N;
        else N = N * N % M;
    }
    return ret;
}

constexpr long long MOD = 998244353;

int main() {
    int t;
    cin >> t;
    string hello = "helloworld";
    for(int tmp = 0;tmp < t;tmp++) {
        int n;
        cin >> n;
        string s;
        cin >> s;
        vector<string> ret;
        for(int i = 0;i < n - 9;i++) {
            bool isok = true;
            for(int j = 0;j < 10;j++) {
                if(s[i + j] != hello[j] && s[i + j] != '?') isok = false;
            }
            if(isok) {
                string t = s;
                for(int j = 0;j < 10;j++) {
                    t[i + j] = hello[j];
                }
                for(int j = 0;j < n;j++) {
                    if(t[j] == '?') t[j] = 'a';
                }
                ret.push_back(t);
            }
        }

        if(ret.empty()) cout << -1 << endl;
        else {
            sort(ret.begin(),ret.end());
            cout << ret[0] << endl;
        }
    }
}