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