#include <bits/stdc++.h>
#define REP(i, a, n) for(ll i = ((ll) a); i < ((ll) n); i++)
using namespace std;
typedef long long ll;

string S;

int main(void) {
  cin >> S;

  ll ans = 0;
  REP(i, 0, S.length() * 2 - 1) {
    if(i % 2 == 0) {
      ll cnt = 1;
      REP(j, 1, S.length()) {
        char c1 = i / 2 + j < S.length() ? S[i / 2 + j] : ' ';
        char c2 = i / 2 - j >= 0 ? S[i / 2 - j] : ' ';
        if(c1 != ' ' && c1 == c2) cnt += 2;
      }
      ans = max(ans, cnt);
    } else {
      ll cnt = 0;
      REP(j, 0, S.length()) {
        char c1 = i / 2 + j + 1 < S.length() ? S[i / 2 + j + 1] : ' ';
        char c2 = i / 2 - j >= 0 ? S[i / 2 - j] : ' ';
        if(c1 != ' ' && c1 == c2) cnt += 2;
      }
      ans = max(ans, cnt);
    }
  }
  cout << ans << endl;
}