N,M=map(int, input().split())
S=input()
W,A,C=[],[],[]
for i in range(len(S)):
  if S[i]=='W':
    W.append(i)
  elif S[i]=='A':
    A.append(i)
  else:
    C.append(i)

AW,AC=A[-len(W):],A[:len(C)]
f=0
for i in range(len(W)):
  if W[i]>AW[i]:
    f=1 
for i in range(len(C)):
  if A[i]>C[i]:
    f=1
if f==0:
  print('Yes')
else:
  print('No')