ABC076 C:Dubious Document 2

void solve(string s) {
    for (auto &c : s) {
        if (c == '?') c = 'a';
    }
    reverse(s.begin(), s.end());
    cout << s << endl;
    exit(0);
}

signed main() {
    string s, t;
    cin >> s >> t;
    reverse(s.begin(), s.end());
    reverse(t.begin(), t.end());
    const int s_len = (int)s.size();
    const int t_len = (int)t.size();

    rep(i, 0, s_len) {
        if (s[i] == t[0] || s[i] == '?') {
            string sa = s.substr(i, t_len);
            if ((int)sa.size() < t_len) continue;

            bool ok = true;
            rep(j, 0, t_len) {
                if (sa[j] != t[j] && sa[j] != '?') {
                    ok = false;
                    break;
                }
            }
            if (ok) {
                rep(j, 0, t_len) {
                    s[i++] = t[j];
                }
                solve(s);
            }
        }
    }
    puts("UNRESTORABLE");
}