/*
ID: iraqibu1
PROG: calfflac
LANG: C++
*/


#include <cstdio>
#include <algorithm>
#include <queue>
#include <string.h>
#include <ctype.h>
using namespace std;

#define MAX 20005

char str[MAX], cpy[MAX], res[MAX], bal[100];
int max_palin, start, end;

int palin_len(int from, int to)
{
    int i, j;
    int flag = 1, count = 0;

    for(i=from,j=to; i<j; )
    {
        if(isalpha(cpy[i]) && isalpha(cpy[j]))
        {
            if(cpy[i] == cpy[j])
            {
                //printf("%c %c\n", cpy[i], cpy[j]);
                count++;
                i++;
                j--;
            }
            else
            {
                flag = 0;
                break;
            }
        }
        else if(isalpha(cpy[i]))
            j--;
        else if(isalpha(cpy[j]))
            i++;
        else
        {
            i++;
            j--;
        }
    }
    if(!flag) return 0;
    if(flag) return ((i==j)? 2*count+1 : 2*count);
}

int main()
{
    freopen("calfflac.in", "r", stdin);
    freopen("calfflac.out", "w", stdout);
    int len, temp;
    int i, j;
    char ch;
    //gets(str);
    i = 0;
    /*while((ch = getchar()) != EOF)
    {
        if(ch != '\n')
            str[i++] = ch;
    }
    str[i] = '\0';
    */
    //gets(str);
    while(gets(bal))
        strcat(str, bal);


    for(i=0 ; str[i] ; i++)
    {
        if(isalpha(str[i]))
            cpy[i] = tolower(str[i]);
        else cpy[i] = str[i];
    }
    cpy[i] = '\0';
    //puts(cpy);
    len = strlen(cpy);
    max_palin = 0;
    for(i=0; i<len; i++)
    {
        if(isalpha(cpy[i]))
        {
            for(j=i; ((j<=(i+2000)) && cpy[j]); j++)
            {
                temp = palin_len(i, j);
                //printf("%d\n", temp);
                if(temp > max_palin)
                {
                    start = i;
                    end = j;
                    max_palin = temp;
                }
                //printf("call hosse!!!\n");
            }
        }
    }
    printf("%d\n", max_palin);
    j = 0;
    for(i=start; i<=end; i++)
        res[j++] = str[i];
    res[j] = 0;
    puts(res);

    //system("pause");
    return 0;
}