package main

import (
  "fmt"
  "os"
)

func getPassedArgs() string {

  if len(os.Args) != 2 {
    fmt.Printf("Exactly 1 argument is needed\n")
    os.Exit(1)
  }

  return os.Args[1]

}

func main() {

  m := map[string]string{
    "305": "Sue",
    "204": "Bob",
    "631": "Jake",
    "073": "Tracy",
  }

  key := getPassedArgs()
  if name := m[key]; name != "" {
    fmt.Println("Hi,", name)
  } else {
    fmt.Println(key, "not found")
    os.Exit(1)
  }

}