#include <iostream>
#include <vector>
#include <utility>
using namespace std;

int main() {
	auto A = vector<pair<int,int>>{{0,0},{1,1},{2,2},{3,3}};
	auto it= A.begin();
    auto it2= it+1;

    for ( ; it != A.end()-1; it++ )
    {
        cout << it->first << " " << it2->first << "\n";
        it2++;
    }
	return 0;
}