# import sys # sys.setrecursionlimit(10**7) # input = sys.stdin.readline # import pypyjit # pypyjit.set_param('max_unroll_recursion=-1') def mp():return map(int,input().split()) def lmp():return list(map(int,input().split())) def lm1(LIST): return list(map(lambda x:x-1, LIST)) def mps(A):return [tuple(map(int, input().split())) for _ in range(A)] def stoi(LIST):return list(map(int,LIST)) def itos(LIST):return list(map(str,LIST)) def atoi(LIST): return [ord(i)-ord("a") for i in LIST] def Atoi(LIST): return [ord(i)-ord("A") for i in LIST] def bitA(X,A):return X & 1<= 2: a = s.popleft() b = s.popleft() if a+b in ["wa","wo","w?","?a","?o"]: continue elif a == "?": s.appendleft(b) else: s.appendleft(b) s.appendleft(a) break #print(s) if len(s) >= 2: print("No") else: print("Yes")