#include <iostream>
#include <vector>
using namespace std;
int main() {
    vector<int> v = {1,2,3,4,5};
    v.push_back(6);
    v.erase(v.begin() + 2);
    v.insert(v.begin() + 1, 10);
    cout << v[3] << endl;
    return 0;
}