S = input()
flag = 0

for i in range(len(S)):
    if i%2 == 0:
        if S[i] == " ":
            flag += 1
            print("No")
            break
    else:
        if S[i] == " ":
            continue
        else:
            flag += 1
            print("No")
            break
if flag == 0:
    print("Yes")