import sys
input = sys.stdin.readline
from collections import *

N, M = map(int, input().split())
S = input()[:-1]
q = deque([])
ban = [False]*len(S)

for i in range(len(S)):
    if S[i]=='C':
        if len(q)==0:
            exit(print('No'))
        else:
            ban[q.popleft()] = True
    elif S[i]=='A':
        q.append(i)

W = 0

for i in range(len(S)):
    if ban[i]:
        continue
    
    if S[i]=='W':
        W += 1
    elif S[i]=='A':
        W -= 1
        
        if W<0:
            exit(print('No'))

print('Yes')