#include <vector>
#include <iostream>

int main(int argc, char const *argv[])
{
    std::vector<std::vector<int> > foo(3, std::vector<int>(3, 1));
    std::vector<int>::iterator foo_it = foo[0].begin();
    std::cout << "*foo_it: " << *foo_it << std::endl;
    foo.push_back(std::vector<int>(3, 2));
    std::cout << "*foo_it: " << *foo_it << std::endl;
    return 0;
}