#include <iostream>
#include <vector>

using namespace std;

void f(int m, vector<int> vec, vector<int>& sd, size_t& count)
{
    if (m == 1)
    {
        for (int i = 0; i<vec.size(); i++)
        {
            count++;
            cout << count << ":";
            for (int k = 0; k<sd.size(); k++)
                cout << sd[k] << " ";
            cout << vec[i] << " " << endl;
        }
    }
    else
    {
        for (int i = 0; i<vec.size(); i++)
        {
            sd.push_back(vec[i]);
            vector<int> temp;
            for (int j = i + 1; j<vec.size(); j++)
            {
                temp.push_back(vec[j]);
            }
            f(m - 1, temp, sd, count);
            sd.pop_back();
        }
    }
}

int main(int argc, char* argv[])
{
    if (argc != 3)
        return 0;

    vector<int> vec;
    for (int i = 0; i<atoi(argv[1]); i++)
        vec.push_back(i + 1);

    vector<int> sd;
    size_t count = 0;

    f(atoi(argv[2]), vec, sd, count);

    return 0;
}