n, m = map(int, input().split())
S = list(input())

a_num = 0
for i in range(2 * (n + m)):
    if S[i] == 'A':
        a_num += 1
    elif S[i] == 'C':
        if a_num > 0:
            a_num -= 1
        else:
            print("No")
            exit()
    else:
        if a_num == n:
            print("No")
            exit()
print("Yes")