n, m = map(int,input().split())
s = input()

w = []
a = []
c = []
for i in range(2*n + 2*m):
	if s[i] == "W":
		w.append(i)
	if s[i] == "A":
		a.append(i)
	if s[i] == "C":
		c.append(i)

mode = 1
for i in range(m):
	if a[i] > c[i]:
		mode = 0
for i in range(n):
	if w[i] > a[i+m]:
		mode = 0

if mode:
	print("Yes")
else:
	print("No")