import sys
input = sys.stdin.readline

T=int(input())

for tests in range(T):
    R=list(input().strip())
    S=input().strip()
    K=int(input())

    if S[0]=="W":
        for i in range(K):
            R[i]="A"

        if "W" in R:
            pass
        else:
            if R.count("?")==1:
                x=R.index("?")
                R[x]="W"

        print("".join(R))

    else:
        if "W" in R:
            count=0
            fl=0
            for i in range(K):
                if R[i]=="A":
                    count+=1
                if R[i]=="?":
                    fl=1

            if count==K-1 and fl==1:
                x=R.index("?")
                R[x]="W"
        count=0
        for i in range(K):
            if R[i]=="A":
                count+=1

        if count==K:
            for i in range(len(R)):
                R[i]="A"

        print("".join(R))