#include #define rep(i,n) for(int i = 0; i < (n); i++) using namespace std; typedef long long ll; int main(){ cin.tie(0); ios::sync_with_stdio(0); string s; cin >> s; int n = int(s.size()), ans = 1; rep(i,n) { int cnt = 0; rep(k,n) if(0 <= i - k && i + k < n) cnt += (s[i - k] == s[i + k]); ans = max(ans, cnt * 2 - 1); } rep(i,n) { int cnt = 0; rep(k,n) if(k) if(0 <= i - k && i + k - 1 < n) cnt += (s[i - k] == s[i + k - 1]); ans = max(ans, cnt * 2); } cout << ans << endl; }