#include 
#include 
#include 
#include 
#include 
using namespace std;
int arr[5];
void rec(int i, vector v) {
    if(i == 3) {
        for(int k = 0; k < v.size(); k++) {
            cout << v[k] << " ";
        }
        cout << endl;
        return;
    }
    rec(i + 1, v);
    vector tmp_v = v;
    tmp_v.push_back(arr[i]);
    rec(i + 1, tmp_v);
}
int main() {
    vector v;
    arr[0] = 1;
    arr[1] = 2;
    arr[2] = 3;
    
    rec(0, v);
    return 0;
}