#include <algorithm>
#include <iostream>
using namespace std;
int main() {
string s, cur, temp;
cin >> s;
if (s.length() == 1) {
cout << s.length();
return 0;
}
int len = 0;
for (int i = 0; i < s.size(); ++i) {
for (int j = i + 1; j < s.size(); ++j) {
cur = s.substr(i, j - i + 1);
temp = cur;
reverse(cur.begin(), cur.end());
if (cur == temp)
len = max(len, j - i + 1);
}
}
cout << len;
return 0;
}

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