#include <iostream>
using namespace std;
bool isIcecreamSandwich(string s){
string n;
for(int i = 0; i <= s.length() / 2; ++i)
if(s[i] != s[s.length() - i - 1] || (n = !i || s[i] != n[n.length() - 1] ? n + s[i] : n).length() > 2)
return false;
return n.length() == 2;
}
int main(){
string s;
getline(cin, s), cout << boolalpha << isIcecreamSandwich(s);
}
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