
fun main(args:Array<String>) {
    val s = readLine()!!.toMutableList()
    if(solve(s)) {
        println("Yes")
    } else {
        println("No")
    }
}

fun solve(s:MutableList<Char>):Boolean {
    if(s.size % 2 != 0) {
        return false
    }
    while (s.size > 0) {
        if(s[0] == 'h' && s[1] == 'i') {
            s.removeAt(0)
            s.removeAt(0)
        } else {
            return false
        }
    }
    return true
}
