#include <iostream>
#include <vector>
#include <string>
#include <cstring>
#include <math.h>
#include <cmath>
#include <limits.h>
#include <map>
#include <set>
#include <queue>
#include <algorithm>
#include <functional>
#include <stdio.h>
using namespace std;

long long MOD = 1000000007;

int main() {
    string S;
    cin >> S;
    int n = S.length();
    int ans = 0;
    for ( int i = 0; i < n; i++ ) {
    for ( int j = 1; i+j-1 < n; j++ ) {
        string s = S.substr( i, j );
        string t = s;
        reverse( t.begin(), t.end() );
        if ( s == t && j != n ) { ans =  max( ans, j ); }
    }
    }
    cout << ans << endl;
    return 0;
}