// Palindrome is a string that is the same forward and backward
package main
import (
	"bufio"
	"fmt"
	"os"
)
func main() {
	scanner := bufio.NewScanner(os.Stdin)
	for scanner.Scan() {
		var str string
		if len(scanner.Text()) > 2 {
			str = palindrome(scanner.Text())
		}
		if len(str) > 2 {
			fmt.Println(str)
		}
	}
	if scanner.Err() != nil {
		fmt.Fprintln(os.Stderr, "Error reading console input")
	}
}
// Returns the longest palindrome in str
func palindrome(str string) string {
	longest := ""
	jobs := 0
	results := make(chan string)
	for k, _ := range str {
		if k > 0 {
			go pal_worker(str, k, results)
			jobs++
		}
	}
	for {
		select {
		case candidate := <-results:
			jobs--
			if len(candidate) > len(longest) {
				longest = candidate
			}
			if jobs == 0 {
				close(results)
				return longest
			}
		}
	}
}
func pal_worker(str string, k int, result chan<- string) {
	longest := string(str[k])
	for i := 1; true; i++ {
		// avoid overrun or underrun
		if k-i < 0 || k+i > len(str)-1 {
			break
		}
		// two identical bytes
		if str[k-i] == str[k+i] {
			longest = string(str[k-i]) + longest + string(str[k+i])
		} else {
			break
		}
	}
	//fmt.Fprintf(os.Stderr, "Worker(%d) result: %s\n", k, longest)
	result <- longest
}

# Couple of ideas
 - make a note of these just to order them in my head
 - write the basic version with no channels
 - test channel closing methods: no more load, no more work, know number of
workers, unknown number of workers and loaders, channel buffer size based
channel closing?
 - create separate channel for loader and worker
 - measure (profile) loader and worker
 - make suggestions: more loader or more worker is needed
 - write tests for the functions