#include<iostream>
#include<list>
using namespace std;

int main() {
   list<int> l{1,2,3,4,5};
   list<int>::iterator it=l.begin();
   it++;
   l.insert(it,100);//prosthetei to 100 prin to 2
   // new list: {1, 100 , 2, 3, 4, 5}

   list<int> new_l={10,20,30,40};
   new_l.insert(new_l.begin(), l.begin(),l.end());
   //prosthetei ta stoixeia ths new_l sto telos ths l

   l.insert(l.begin(),5,10); //prothetei to 10 prin thn arxh 5 fores

   
   return 0;
}