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

pos = [[] for _ in range(3)]
for i, s in enumerate(S):
    pos["WAC".index(s)].append(i)


ok = True

# Wのペア、Aの後ろのほうを貪欲に
A = pos[1][-N:]
for i in range(N):
    if pos[0][i] > A[i]:
        ok = False
        break

# Cのペア、Aの前のほうを貪欲に
A = pos[1][:M]
for i in range(M):
    if A[i] > pos[2][i]:
        ok = False
        break

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