#define _CRT_SECURE_NO_WARNINGS #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include //#include "util.h" using namespace std; typedef unsigned uint; typedef long long ll; typedef unsigned long long ull; //呪文 template ostream& operator << (ostream& ostr, const pair<_KTy, _Ty>& m) { cout << "{" << m.first << ", " << m.second << "}"; return ostr; } template ostream& operator << (ostream& ostr, const map<_KTy, _Ty>& m) { if (m.empty()) { cout << "{ }"; return ostr; } cout << "{" << *m.begin(); for (auto itr = ++m.begin(); itr != m.end(); itr++) { cout << ", " << *itr; } cout << "}"; return ostr; } template ostream& operator << (ostream& ostr, const vector<_Ty>& v) { if (v.empty()) { cout << "{ }"; return ostr; } cout << "{" << v.front(); for (auto itr = ++v.begin(); itr != v.end(); itr++) { cout << ", " << *itr; } cout << "}"; return ostr; } template ostream& operator << (ostream& ostr, const set<_Ty>& s) { if (s.empty()) { cout << "{ }"; return ostr; } cout << "{" << *(s.begin()); for (auto itr = ++s.begin(); itr != s.end(); itr++) { cout << ", " << *itr; } cout << "}"; return ostr; } #define PI 3.14159265358979323846 #define EPS 1e-6 #define MIN(a,b) ((a)<(b)?(a):(b)) #define MAX(a,b) ((a)>(b)?(a):(b)) #define all(x) (x).begin(), (x).end() bool isPalindrome(string S) { int l = 0, r = S.size() - 1; while (l < r) { if (S[l++] != S[r--]) return false; } return true; } int yuki0273() { string S, s; int ans = 0; cin >> S; if (S.size() == 2) { cout << 1 << endl; return 0; } for (int i = 0; i < S.size(); i++) { for (int j = 1; i + j <= S.size(); j++) { s = S.substr(i, j); if (isPalindrome(s)) ans = max(ans, (int)s.size()); } } cout << ans << endl; return 0; } int main() { //clock_t start, end; //start = clock(); yuki0273(); //end = clock(); //printf("%d msec.\n", end - start); return 0; }