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
    
    hello = 'helloworld'
    
    for _ in range(int(input())):
        N = int(input())
        S = list(input())
        
        ans = []
        
        for i in range(N-9):
            f = True
            for j in range(10):
                if S[i+j] != hello[j] and S[i+j] != '?':
                    f = False
                    break
            if f == True:
                tmp = list(S)
                for j in range(10):
                    tmp[i+j] = hello[j]
                for j in range(N):
                    if tmp[j] == '?':
                        tmp[j] = 'a'
                ans.append(''.join(tmp))
        
        if len(ans) == 0:
            print(-1)
            continue
        
        ans.sort()
        print(ans[0])
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
if __name__ == '__main__':
    main()