package main

import (
	"bufio"
	"bytes"
	"fmt"
	"os"
)

func main() {
	ln := 1
	reader := bufio.NewReader(os.Stdin)
	for true {
		// Read first line and make a copy
		line1, _, err1 := reader.ReadLine()
		if err1 != nil {
			break
		}
		// Make a copy.
		copyOfLine1 := make([]byte, len(line1))
		copy(copyOfLine1, line1)
		print(ln, line1)

		// Second line.
		line2, _, err2 := reader.ReadLine()
		if err2 != nil {
			break
		}
		print(ln+1, line2)

		// Problem here - after reading the second line, the line1 is modified??
		if bytes.Compare(line1, copyOfLine1) != 0 {
			fmt.Printf("NOT EQUAL - line1: %s; copy: %s\n", string(line1), string(copyOfLine1))
		}

		// Must read a 3rd line.
		line3, _, err3 := reader.ReadLine()
		if err3 != nil {
			break
		}
		print(ln+2, line3)
		ln += 3
	}
}

func print(ln int, slice []byte) {
	fmt.Printf("%d: %s\n", ln, string(slice))
}