#include <bits/stdc++.h>

using i64 = long long;

const std::string t = "helloworld";

void solve() {
    int n;
    std::cin >> n;
    
    std::string s;
    std::cin >> s;
    
    std::string ans;
    
    for (int i = 0; i + 10 <= n; i++) {
        bool ok = true;
        std::string a = s;
        for (int j = 0; j < 10; j++) {
            if (a[i + j] != '?' && a[i + j] != t[j]) {
                ok = false;
            }
            a[i + j] = t[j];
        }
        if (!ok) {
            continue;
        }
        for (int j = 0; j < n; j++) {
            if (a[j] == '?') {
                a[j] = 'a';
            }
        }
        if (ans.empty() || ans > a) {
            ans = a;
        }
    }
    
    if (ans.empty()) {
        ans = "-1";
    }
    
    std::cout << ans << "\n";
}

int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
    
    int t;
    std::cin >> t;
    
    while (t--) {
        solve();
    }
    
    return 0;
}