function solve(input) {
    let result = {};
    input.map(x => {
        let [name, ...grades] = x.split(" ")
        grades = grades.map(Number)
        !result[name] ? result[name] = grades
            : result[name] = result[name].concat(grades)
    })

    Object.keys(result)
        .sort()
        .forEach(function (v) {
            let grades = result[v]
            let avg = grades.reduce((a, v) => a + v) / grades.length
            console.log(`${v}: ${avg.toFixed(2)}`)
        });
}