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 Rust (1.15.1) (judge verdict: Accepted)

use std::io;

fn main() {
    let mut target_str = String::new();
    io::stdin().read_line(&mut target_str).unwrap();
    let target_str = target_str.trim();

    let mut count: usize = 0;

    loop {
        match target_str.chars().nth(count) {
            Some('h') => match target_str.chars().nth(count + 1) {
                Some('i') => {
                    count += 2;
                }
                _ => {
                    println!("No");
                    break;
                }
            },
            None => {
                println!("Yes");
                break;
            }
            _ => {
                println!("No");
                break;
            }
        };
    }
}