function schoolGrades(input) {
    let students = {}
    input.forEach(line => {
        let studentInfo = line.split(" ")
        let name = studentInfo.shift()
        let grades = studentInfo.map(x => Number(x))
        if (!students[name]) students[name] = []
        students[name] = students[name].concat(grades)
    });
    let sortedStudents = Object.entries(students).sort((a, b) => a[0].localeCompare(b[0]))
    for (let [name, grade] of sortedStudents) {
        let sum = 0
        grade.forEach(grades => sum += grades)
        let avarageGrade = grade.reduce((a, b) => a + b) / grade.length
        console.log(`${name}: ${avarageGrade.toFixed(2)}`)
    }
}