package main

import "io"
import "log"
import "os"

var reader io.Reader

func main() {
	if len(os.Args) <= 1 {
		reader = os.Stdin
	} else {
		readers := []io.Reader{}
		for _, fname := range os.Args[1:] {
			if f, err := os.Open(fname); err != nil {
				log.Fatalln(err)
			} else {
				defer f.Close()
				readers = append(readers, f)
			}
		}
		reader = io.MultiReader(readers...)
	}
	io.Copy(os.Stdout, reader)
}