/*
ID : bristy11
LANG : C++
TASK : calfflac
*/
        //Bristy Sikder Loves U
# include <iostream>
# include <stdio.h>
# include <map>
# include <cstring>
# include <vector>
using namespace std;

int main()
{
    //data structures
    int a,b,c,size,alph,check;
    char line[40000]; // the main string
    char str[85];
    char smlet[]={"abcdefghijklmnopqrstuvwxyz"};
    char caplet[]={"ABCDEFGHIJKLMNOPQRSTUVWXYZ"};
    vector <char> pal;
    map<int,int>tag;

    freopen("calfflac.in","r",stdin);
    freopen("calfflac.out","w",stdout);

    //input
    size=0;
    while (gets(str)!=NULL){
        int k;
        k=strlen(str);
        for(b=0;b<k;b++) line[size+b]=str[b];
        line[size+k]=1;
        size+=k+1;
        //cout << line << "\n";
    }
    /*for(int i=0;i<size;i++)
    {
        if(line[i]==1)
            printf("\n");
        else
        printf("%c",line[i]);
    }*/


  //  printf(":\n");
    //sorting out the letters
    alph=0;
    for(a=0;a<size;a++){
        for(b=0;b<strlen(smlet);b++){
            if(line[a]==smlet[b]) {
                pal.push_back(caplet[b]);
                tag[alph]=a;
                alph++;
                //cout << line[a];
            }
        }
        for(b=0;b<strlen(caplet);b++){
            if(line[a]==caplet[b]) {
                pal.push_back(caplet[b]);
                tag[alph]=a;
                alph++;
                //cout << line[a];
            }
        }
    }
    //for(a=0;a<alph;a++) cout << pal[a] << " " << a << "  ";
    //cout <<  endl;

    //processing
    int finlen=0;
    int finbeg=0;
    int finend=0;
    for(a=0;a<alph-1;a++){
        for(b=min(a+1999,alph-1);b>=max(a+1,a+finlen);b--){ //  b<=size-1;  b>finlen;
            //palindrome check
            //cout << a << " " << b << endl;
            check=0;
            for(c=0;c<=(b-a)/2;c++){
                //cout << pal[a+c] << pal[b-c] << " " <<a+c<< " " << b-c << endl;
                if(pal[a+c]!=pal[b-c]) {
                    check=1;
                    break;
                }
            }
            if(check==1) continue;
            else {
                finlen=b-a+1;
                finbeg=tag[a];
                finend=tag[b];
                //cout << finlen << endl;
                //for(a=finbeg;a<=finend;a++) cout << line[a];
                //cout << endl;
                break;
            }
        }
    }

    //results
    cout << finlen << endl;

    for(a=finbeg;a<=finend;a++)
    {
        if(line[a]==1) printf("\n");
        else cout << line[a];

    }
    printf("\n");
    return 0;
}