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: Wrong Answer)

fn main() {
    let mut str = String::new();
    std::io::stdin().read_line(&mut str);
    str.trim_right().to_owned();
    let mut flag = true;
    for i in 0..str.len()/2{
        let ch2 = &str[i*2..i*2+2];
        if ch2 != "hi" {
            flag = false;
            break;
        }     }
    if str.len() %2 != 0 {
        flag = false;
    } 
    if flag {
        println!("Yes");    
    } else {
        println!("No");
    }
}