Problem:
Score : 100 points

Problem Statement

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.

Constraints

The length of S is between 1 and 10 (inclusive).

S is a string consisting of lowercase English letters.

Input

Input is given from Standard Input in the following format:

S

Output

If S is a Hitachi string, print Yes; otherwise, print No.

Sample Input 1

hihi

Sample Output 1

Yes

hihi is the concatenation of two copies of hi, so it is a Hitachi string.

Sample Input 2

hi

Sample Output 2

Yes

Sample Input 3

ha

Sample Output 3

No

Solution in Python (3.4.3) (judge verdict: Accepted)

from sys import stdin
def main():
	readline=stdin.readline
	S=readline().strip()
	hflag=False
	iflag=True
	for i in range(len(S)):
		if S[i]=="h" and iflag:
			hflag=True
			iflag=False
		elif S[i]=="i" and hflag:
			iflag=True
			hflag=False
		else:
			print("No")
			break
	else:
		if hflag==False and iflag:
			print("Yes")
		else:
			print("No")
if __name__=="__main__":
	main()