c++) 2차원 vector의 user input

vector<vector<int>> v(n);
	// input
    for(int i = 0; i < n; i++) {
        int num1;
        cin >> num1;
        v[i].push_back(num1);
        int num2;
        cin >> num2;
        v[i].push_back(num2);
    }
    
    // read
    for(auto row = v.begin(); row != v.end(); row++) {
        for(auto col = row->begin(); col != row->end(); col++) {
            cout << *col << ' ';
        } cout << endl;
    }