A string is called square if it is some string written twice in a row. For example, the strings "aa", "abcabc", "abab" and "baabaa" are square. But the strings "aaa ...

#define rep(i,a,b) for(ll i=a;i<b;i++) #define repd(i,a,b) for(ll i=b-1;i>=a;i--) ll lmin(vl arr){return *min_element(arr.begin(),arr.end());} ll lmax(vl arr){return ...