s = input().strip()
n = len(s)
if n % 2 == 0:
    print("No")
else:
    valid = True
    for i in range(n):
        pos = i + 1
        if pos % 2 == 1:
            if not s[i].islower():
                valid = False
                break
        else:
            if s[i] != ' ':
                valid = False
                break
    print("Yes" if valid else "No")