from sys import stdin
def main():
    #入力
    readline=stdin.readline
    s=readline().strip()

    for i in range(len(s)):
        if i%2==0:
            if s[i]==" ":
                print("No")
                break
        else:
            if s[i]!=" ":
                print("No")
                break
    else:
        print("Yes")
if __name__=="__main__":
    main()