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

int main(){ 
    list<int> list1={1,2,3,4};
    list<int> list2={5,6,7,8};
    list<int>::iterator it;
    it= list1.begin();
    ++it;
    list1.splice(it,list2);
    list2.splice(list2.begin(),list1,it);

    return 0;
}