import sys
input = sys.stdin.readline

T=int(input())
for _ in range(T):
    N=int(input())
    S=list(input().strip())
    idx = -1
    for i in range(N-10+1):
        for j,t in enumerate("helloworld"):
            u = S[i+j]
            if u=="?":continue
            if u!=t:break
        else:
            idx=i
    if idx==-1:
        print(-1)
    else:
        for j,t in enumerate("helloworld"):
            S[idx+j]=t
        for i in range(len(S)):
            if S[i]=="?":
                S[i]="a"
        print("".join(S))