//sanchi ca stiu ca nu e buna
#include <fstream>
#include <iostream>
#include <string.h>
using namespace std;
ifstream fin("palm.in");
ofstream fout("palm.out");
int n,v[500],sp[500],maxim;
char s[500];
int main(){
    fin>>s;
    v[0]=1;
    sp[0]=s[0]-'0';
    for(int i=1;i<strlen(s);i++){
        if(s[i-1]>s[i])
            v[i]=v[i-1]-1;
        else
            v[i]=v[i-1]+1;
        sp[i]=sp[i-1]+(s[i]-'0');

    }
    for(int i=0;i<strlen(s);i++){
        for(int j=0;j<strlen(s);j++)
            if(v[j]==v[i]&&i!=j){
            if(s[j]-s[(i-j)/2]==s[i+(i-j)/2]-s[i]||s[j]-s[(i-j)/2-1]==s[i+(i-j)/2-1]-s[i])
                maxim=i-j+1;
        }
    }
    fout<<maxim;
    return 0;
}