import numpy
a=input()
b=False
for i in range(len(a)):
    if(len(a)%2!=0):
        if(a[i]!=" "):
            b=True
    if(len(a)%2==0):
        if(a[i]==" "):
            b=True
if(b==True):
    print("No")
else:
    print("Yes")