grades, avg

function solve(input) {

    let list = {};

    for (let current of input) {

        let [name, ...grades] = current.split(' ');
        grades = grades.map(Number)


        if (list.hasOwnProperty(name)) {

            let existingGrades = list[name];
            list[name] = [...existingGrades, ...grades];
        } else {
            list[name] = grades;
        }
    }

    function avg(x) {

        let sum = 0;
        for (let current of x) {
            sum += current;
        }
        return sum / x.length
    }

    let sorted = Object.entries(list)
        .sort((a, b) => avg(a[1]) - avg(b[1]));


    for (let [name, grades] of sorted) {

        console.log(name + ': ' + grades.join(', '));
    }

}


solve(['Lilly 4 6 6 5',
    'Tim 5 6',
    'Tammy 2 4 3',
    'Tim 6 6'
])

/*

*/