def check(S,a,b):
    k=0
    for i in range(len(S)):
        if S[i]==a:
            k+=1
        elif S[i]==b:
            k-=1
        if k<0:
            return False
    return True

def solve():
    N,M=map(int,input().split())
    S=input()

    return check(S,"A","C") and check(S[::-1], "A","W")

#==================================================
print("Yes" if solve() else "No")