s = input()
s = list(s)

a1 = [a for i,a in enumerate(s) if i%2 == 0]
a1 = ''.join(a1)
a2 = [a for i,a in enumerate(s) if i%2 != 0]
a2 = ''.join(a2)
#print(a1)
#print(a2)
if a1 == a1.lower() and ' ' not in a1 and a2 == ' '*len(a2):
    print('Yes')
else:
    print('No')