#include<bits/stdc++.h>
using namespace std;


int a[3]={1,2,3},i,j,k;
vector<int>v;

void print()
{
    for(i=0;i<3;i++)
        cout<<v[i]<<" ";
    cout<<endl;

}

void backtrack(int depth)
{
    if(depth>2)
    {
        print();
        return;
    }

    v.push_back(a[depth]);
    backtrack(depth+1);
    v.pop_back();
    backtrack(depth+1);
}
int main()
{
    backtrack(0);
    return 0;
}