```cpp #pragma GCC optimize(3,"Ofast","inline") #pragma GCC optimize(2) #include <bits/stdc++.h> using namespace std; bool is(string s){ string tmp = s; reverse(s.begin(),s.end()); return s==tmp; } int maxn = 1; int main(){ string s; cin>>s; for(int i=0;i<s.size();i++){ for(int j=1;j+i<=s.size();j++){ string tmp = s.substr(i,j); if(is(tmp)){ maxn = max(maxn,(int)tmp.size()); } } } cout<<maxn; return 0; }