Beer Stock

package main

import (
    "fmt"
  "math"
  "strconv"
)

func main() {
    var neededBeers, deliveredBeers int64
    fmt.Scanln(&neededBeers)

    var input1, input2 string
    fmt.Scan(&input1)
    fmt.Scan(&input2)

    for (input1 + " " + input2) != "Exam Over" {
        amount, _ := strconv.ParseInt(input1, 10, 64)
        beerPackage := input2
        if beerPackage == "sixpacks" {
            amount *= 6
        } else if beerPackage == "cases" {
            amount *= 24;
        }
        deliveredBeers += amount
        fmt.Scan(&input1)
        fmt.Scan(&input2)
    }

    deliveredBeers -= deliveredBeers / 100
    diff := int64(math.Abs(float64(neededBeers - deliveredBeers)))
    cases := diff / 24
    sixpacks := diff % 24 / 6
    beers := diff % 6

    if deliveredBeers >= neededBeers {
        fmt.Printf("Cheers! Beer left: %d cases, %d sixpacks and %d beers.", cases, sixpacks, beers);
    } else {
        fmt.Printf("Not enough beer. Beer needed: %d cases, %d sixpacks and %d beers.", cases, sixpacks, beers);
    }
}