function checkHitachi(S) {

    //hihi, hiii, dadahi, dahiida

    let pass = true;

    S.split('hi').forEach((v) => {
        if (v.length > 0) {
            pass = false;
        }
    })

    return pass;
}


function checkTest() {

    let pass = true;
    if (checkHitachi('ha') !== false) {
        pass = false;
    }
    if (checkHitachi('hii') !== false) {
        pass = false;
    }
    if (checkHitachi('hihi') !== true) {
        pass = false;
    }
    if (checkHitachi('hi') !== true) {
        pass = false;
    }

    return pass;
    
}

if (checkTest()) {
  return 'Yes'
} else {
  return 'No'
}