function Main(str){
    var index = str.indexOf("hi")
    while(index!=-1){
        str = str.substring(index+2)
        index = str.indexOf("hi")
    }
    if(str.length==0){
        console.log("Yes")
    } else {
        console.log("No")
    }
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));