s = input().replace(" ", "#")

count = 0
for i in range(len(s)):
    if i % 2 == 0 and s[i] != "#":
        count += 1
    if i % 2 == 1 and s[i] == "#":
        count += 1

if count == len(s):
    print("Yes")
else:
    print("No")