def main():
    try:
        import pypyjit
        pypyjit.set_param('max_unroll_recursion=-1')
    except:
        pass
    try:
        import sys
        sys.setrecursionlimit(10**7)
    except:
        pass
    from math import sqrt,sin,cos,tan,ceil,radians,floor,gcd,exp,log,log10,log2,factorial,fsum
    import heapq
    from bisect import bisect_left, bisect_right
    import copy
    from collections import deque,Counter,defaultdict
    from itertools import permutations,combinations
    from decimal import Decimal,ROUND_HALF_UP
    #tmp = Decimal(mid).quantize(Decimal('0'), rounding=ROUND_HALF_UP)
    from functools import lru_cache, reduce
    #@lru_cache(maxsize=None)
    from operator import add,sub,mul,xor,and_,or_
    INF = 10**18
    mod1 = 10**9+7
    mod2 = 998244353
    
    #DecimalならPython
    
    for _ in range(int(input())):
        N = int(input())
        S = list(input())
        
        flag = False
        for i in range(N-9):
            if S[i] == 'h' or S[i] == '?':
                if S[i+1] == 'e' or S[i+1] == '?' :
                    if S[i+2] == 'l' or S[i+2] == '?' :
                        if S[i+3] == 'l' or S[i+3] == '?' :
                            if S[i+4] == 'o' or S[i+4] == '?' :
                                if S[i+5] == 'w' or S[i+5] == '?' :
                                    if S[i+6] == 'o' or S[i+6] == '?' :
                                        if S[i+7] == 'r' or S[i+7] == '?' :
                                            if S[i+8] == 'l' or S[i+8] == '?' :
                                                if S[i+9] == 'd' or S[i+9] == '?' :
                                                    S[i] = 'h'
                                                    S[i+1] = 'e'
                                                    S[i+2] = 'l'
                                                    S[i+3] = 'l'
                                                    S[i+4] = 'o'
                                                    S[i+5] = 'w'
                                                    S[i+6] = 'o'
                                                    S[i+7] = 'r'
                                                    S[i+8] = 'l'
                                                    S[i+9] = 'd'
                                                    flag = True
                                                    break
        
        if flag == True:
            for i in range(N):
                if S[i] == '?':
                    S[i] = 'a'
            print(''.join(S))
        else:
            print(-1)
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
if __name__ == '__main__':
    main()