# 右からN個のAはWA用
# 左からM個のAはAC用
# A, AC用のAの場所をリスト化して、1つずつAより右にあればOK
# WAも同様
# 両方のテストをクリアすればYesか

N, M = map(int, input().split())
S = input()
A_list = []
C_list = []
W_list = []
for i in range(N*2+M*2):
    if S[i] == 'A':
        A_list.append(i)
    elif S[i] == 'C':
        C_list.append(i)
    elif S[i] == 'W':
        W_list.append(i)
#print(A_list)
A_forAC = A_list[:M]
A_forWA = A_list[M:]
        
#print(A_forAC, C_list)
#print(W_list, A_forWA)

AC_test = True
for i in range(M):
    if A_forAC[i] > C_list[i]:
        AC_test = False
        
WA_test = True
for i in range(N):
    if W_list[i] > A_forWA[i]:
        WA_test = False

if AC_test == True and WA_test == True:
    print('Yes')
else:
    print('No')