N, M = [int(s) for s in input().split()]
S = [*input()]
T = input()

if T == "Warong":
    S[:M] = ["A"] * M
    if "W" not in S[M:] and S[M:].count("?") == 1:
        S[S.index("?")] = "W"

else:
    if "W" in S[M:] and all(s in ("A", "?") for s in S[:M]) and S[:M].count("?") == 1:
        S[S[:M].index("?")] = "W"
    elif all(s == "A" for s in S[:M]):
        S[M:] = ["A"] * (N - M)

print(*S, sep="")