import sys

def input():
    return sys.stdin.readline()[:-1]

def main():
    s = input()
    for k in range(len(s)):
        if k%2 == 0:
            if s[k] == " ":
                print("No")
                exit(0)
        else:
            if s[k] != " ":
                print("No")
                exit(0)
    print("Yes")

if __name__ == '__main__':
    main()