Golang并发问题

package main
import (
  "bufio"
  "fmt"
  "os"
  "runtime"
  "sync"
  "time"
)
var wg1 sync.WaitGroup
var FLAG int = 1
func prin() {
  for i:=1; ;i++ {
    fmt.Println(i)
    time.Sleep(5 * 1000000000)
    if FLAG==0 {
      wg1.Done()
      os.Exit(0)
    }
  }
}
func loop() {
  for {
    inputReader := bufio.NewReader(os.Stdin)
    input, _ := inputReader.ReadString('\n')
    if input != "\n"{
      fmt.Print("The input type: ", input)
    } else {
      wg1.Done()
      FLAG=0
    }
  }
}
func main() {
  runtime.GOMAXPROCS(2)
  wg1.Add(1)
  go prin()
  go loop()
  wg1.Wait()
}