#include <iostream>
#include <string>
#include <queue>
#include <stack>
#include <algorithm>
#include <list>
#include <vector>
#include <complex>
#include <utility>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <climits>
#include <bitset>
#include <ctime>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <cassert>
#include <cstddef>
#include <iomanip>
#include <numeric>
#include <tuple>
#include <sstream>
#include <fstream>

#define REP(i,n) for(int (i)=0;(i)<(n);(i)++)
#define FOR(i,a,b) for(int (i)=(a);(i)<(b);(i)++)
#define RREP(i,a) for(int (i)=(a)-1;(i)>=0;(i)--)
#define FORR(i,a,b) for(int (i)=(a)-1;(i)>=(b);(i)--)
#define PI acos(-1.0)
#define DEBUG(C) cout<<C<<endl;
#define VI vector<int>
#define VII vector<VI>
#define VL vector<long>
#define VLL vector<VL>
#define VD vector<double>
#define VDD vector<VD>
#define PII pair<int,int>
#define PDD pair<double,double>
#define PLL pair<long,long>
#define ALL(a) (a).begin(),(a).end()
#define SORT(a) sort(ALL(a))
#define REVERSE(a) reverse(ALL(a))
#define MP make_pair
#define EP emplace_back
#define FORE(a,b) for(auto &&a:b)

using namespace std;
typedef long long LL;
typedef unsigned long long ULL;
const int INF=1e9;
const int MOD=INF+7;

bool check(string s){
    REP(i,s.size()/2){
        if(s[i]!=s[s.size()-i-1]) return false;
    }
    return true;
}

int main (void){
    string s;
    cin>>s;
    int ans=0;
    REP(i,s.size()){
        REP(j,s.size()){
            if(i==0 && j==s.size()-1) continue;
            string sc=s.substr(i,j-i);
            if(check(sc)) ans=max(ans,(int)sc.size());
        }
    }
    cout<<ans<<endl;
}