A Hitachi string is a concatenation of one or more copies of the string `hi`.  For example, `hi` and `hihi` are Hitachi strings, while `ha` and `hii` are not.  Given a string S, determine whether S is a Hitachi string.
S = input()

s_hitachi = list("hitachi")

ans = []
for i in range(len(s_hitachi)):
  ans.append("".join(s_hitachi[0:i+1]))
  

if S in ans:
  print("Yes")
else:
  print("No")
S = input()

a = len(S)
if a%2==1:
  print("No")
  exit()
for i in range(0,a,2):
  if S[i:i+2]!="hi":
    print("No")
    break
  else:
    print("Yes")
    break