5.SchoolRegister

function Grades(input){

   let ArrStudents=[];

   let ArrNewYearStudents=[];
   let gradesArr=[];

    let GradesAvgScore={};
    for (const stud of input) {

        let [studentName,Grade,AverageScore]= stud.split(',');
        let indexst=studentName.indexOf(':');
        let name=studentName.substring(indexst+1,studentName.length);

        let idexgr=Grade.indexOf(':');
        let grade=Grade.substring(idexgr+1,Grade.length);
        let iavr=AverageScore.indexOf(':');
        let avgscore=AverageScore.substring(iavr+1,AverageScore.length);

        let gradenum=Number(grade.trim());
        let avgnum=Number(avgscore.trim());

        if(avgnum >3){
        let student={name:name.trim(), grade:gradenum, avgeragescore:avgnum};
        ArrStudents.push(student);

        let objStudent=ArrNewYearStudents.find(s=> s.grade==gradenum);
        if(!objStudent && avgnum > 3){
            gradesArr.push(grade.trim());
        ArrNewYearStudents.push({grade:gradenum, students:'', avgscore:0});
        }
    }

    }

    let namestudents='';


       for (const student of ArrNewYearStudents) {
        let allstudents='';
        let avggr=0;
        let sumavg=0;
        let countst=0;
        let CStudents=[];
        for (let i=0; i< ArrStudents.length; i++) {
            let g=ArrStudents[i].grade;

        if(student.grade== g && ArrStudents[i].avgeragescore >3){
            countst ++;
            sumavg += ArrStudents[i].avgeragescore;
            CStudents.push(ArrStudents[i].name)
        }

       }
       avggr= sumavg/countst;

       student.avgscore=avggr;
       student.students=CStudents.join(', ');

      }

      gradesArr.sort((a,b)=> a-b);


for (let j = 0; j < gradesArr.length; j++) {
    let student= ArrNewYearStudents.find(s=> s.grade==gradesArr[j] );
    console.log(`${student.grade+1} Grade`);
    console.log(`List of students: ${student.students}`);

    console.log(`Average annual score from last year: ${student.avgscore.toFixed(2)}\n`)

}
}