#include "bits/stdc++.h"
using namespace std;
#define fastcin {\
    cin.tie(0);\
    ios::sync_with_stdio(false);\
}
#define rep(i, a, b) for(int i = a; i < b; i++)
#define rrep(i, a, b) for(int i = a; i >= b; i--)
#define fore(i, a) for(auto &i:a)
#define print(x) cout << x << "\n"
#define SORT(a, n) sort(a, a+n);
#define REVERSE(a,n) reverse(a,a+n);
#define VSORT(v) sort(v.begin(), v.end());
#define VREVERSE(v) reverse(v.begin(), v.end());
#define MOD 1000000007
#define yes "YES"
#define no "NO"
typedef long long ll;

bool pmod(string s, int m, int p) {
    int size = s.size(), tmp = 0;
    rep(i, 0, size) {
        tmp = (tmp*p + s[i]-'0') % m;
    }
    bool b;
    if(tmp) b = false;
    else b = true;
    return b;
}

int main() {
    fastcin;
    string S;
    cin >> S;
    int len = S.length(), tmp, ans = 0;
    rep(i, 1, len-1) {
        int klen = min(i, len-i-1);
        tmp = 1;
        rep(j, 1, klen+1) {
            if(S[i-j]==S[i+j]) tmp += 2;
        }
        ans = max(tmp, ans);
    }
    print(ans);
    return 0;
}