34:回文子串
#include<bits/stdc++.h>
using namespace std;
bool pd(string s){int n = s.size(); int i=0, j=n-1;while (i<j)if (s[i]==s[j]){i++;j--;}elsereturn false;return true;
}
int main(){string s;cin >> s;int n = s.size(); for (int len= 2; len<=s.size(); len++)for (int start = 0; start<=n -len; start++)if ( pd(s.substr(start, len)) )cout << s.substr(start, len) << endl;return 0;
}