#include using namespace std; typedef long long ll; #define F first #define S second #define pii pair #define eb emplace_back #define all(v) v.begin(), v.end() #define rep(i, n) for (int i = 0; i < n; ++i) #define rep3(i, l, n) for (int i = l; i < n; ++i) #define chmax(a, b) a = (a >= b ? a : b) #define chmin(a, b) a = (a <= b ? a : b) #define out(a) cout << (a) << endl #define outa(a, n) rep(_, n) cout << a[_] << " "; cout << endl #define SZ(v) (int)v.size() #define inf (int)(1e9+7) #define abs(x) (x >= 0 ? x : -(x)) int main() { ios::sync_with_stdio(false); cin.tie(0); string s; cin >> s; // out(SZ(s)); int ans = 0; if (ans % 2 == 0) { int c = 0; rep(i, SZ(s) / 2) if (s[SZ(s) / 2 - 1 - i] == s[SZ(s) / 2 + i]) c += 2; chmax(ans, c); } rep(i, SZ(s)) { string t = s; int c = 1; rep3(j, 1, min(i, SZ(s) - (i + 1)) + 1) { if (s[i - j] == s[i + j]) c += 2; } // out(c); chmax(ans, c); } out(ans); }