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()) {
  console.log('Yes')
} else {
  console.log('No')
}