package main

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

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Scan()
	row := sc.Text()

	max := 1
	if len(row) == 2 {
		fmt.Println(1)
		return
	}
	for i := 0; i < len(row)-1; i++ {
		for j := i + 1; j < len(row); j++ {
			diff := (j - i) + 1
			for k := 0; k <= diff/2; k++ {
				if row[i+k] != row[j-k] {
					diff = 0
					break
				}
			}
			if diff > max {
				max = diff
			}
		}
	}

	fmt.Println(max)
}