def solve():
    N, M = map(int, input().split())
    S = input()
    W = input()
    
    ans = list(S)
    if W == "Yes":
        for i in range(M):
            ans[i] = 'A'
        if S.count('A') == N - 1:
            for i in range(N):
                if S[i] != 'A': S[i] = 'W'
    else:
        if all(c == 'A' for c in S[:M]):
            for i in range(M, N):
                ans[i] = 'A'
        elif any(c == 'W' for c in S[M:]) and S[:M].count('A') == M - 1:
            for i in range(M):
                if S[i] != 'A': S[i] = 'W'
    print(''.join(ans))

if __name__ == "__main__":
    solve()