09. On Time for the Exam

function student (...input) {

    let hourOfExamen=Number(input.shift());
    let minuteOfExamen=Number(input.shift());
    let hourOfArraving=Number(input.shift());
    let minuteofArraving=Number(input.shift());

    let timeOfExamen=hourOfExamen*60+minuteOfExamen;
    let timeOfArriving=hourOfArraving*60+minuteofArraving;
    let time=timeOfExamen-timeOfArriving;
    let differenthour=Math.abs(~~(time/60));
    let differentminutes=Math.abs(time % 60);

    if (differenthour>0 && differentminutes<10) {
        differentminutes='0'+differentminutes
    }

    if (time==0) {
        console.log('On time');
    } else if (time>0 && time<=30) {
        console.log('On time');
        console.log(`${differentminutes} minutes before the start`)

    } else if (time>30 && time<=59){
        console.log('Early');
        console.log(`${differentminutes} minutes before the start`);
    } else if (time>59) {
        console.log('Early');
        console.log(`${differenthour}:${differentminutes} hours before the start`);
    }
    else if (time>=-59 && time<0) {
        console.log('Late');
        console.log(`${differentminutes} minutes after the start`);
    } else if (time<-59) {
        console.log('Late');
        console.log(`${differenthour}:${differentminutes} hours after the start`);
    }
}