#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

#define RREP(i,s,e) for (i = s; i >= e; i--)
#define rrep(i,n) RREP(i,n,0)
#define REP(i,s,e) for (i = s; i < e; i++)
#define rep(i,n) REP(i,0,n)
#define INF 1e8

typedef long long ll;

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

int main() {
    int i, j, ans;
    string s;
    cin >> s;
    REP (i,1,s.size()) {
        rep (j,s.size()-i+1) {
            if (check(s.substr(j,i)))
                ans = i;
        }
    }
    cout << ans << endl;
    return 0;
}