import java.util.ArrayList;

class Combination {

    ArrayList<ArrayList> _E = new ArrayList<ArrayList>();
    int _n;
    int _k;

    Combination(int n, int k) {
        _n = n;
        _k = k;

        if (_k > _n || _k < 0 || _n < 0) {
            _n = 0;
            _k = 0;
        }
        int temp[] = new int[_k];

        Permutation _p = new Permutation(_n, _k);

        for (int i = 0; i < _p.getSize(); ++i) {
            _p.getElements(i, temp);

            if (isUniqueElement(temp) == true) {
                ArrayList<Integer> Nums = new ArrayList<Integer>();
                for (int j = 0; j < _k; ++j) {
                    Nums.add(temp[j]);
                }
                _E.add(Nums);
            }
        }

    }

    public int getN() {
        return _n;
    }

    public int getK() {
        return _k;
    }

    public void getElements(int count, int val[]) {
        ArrayList<Integer> temp = new ArrayList<Integer>();
        if (count < getSize()) {
            temp = _E.get(count);
            for (int i = 0; i < temp.size(); ++i) {
                val[i] = temp.get(i);
            }
        }
    }

    public String toString(int count) {
        ArrayList<Integer> temp = new ArrayList<Integer>();
        temp = _E.get(count);
        String result = "";
        for (int i = 0; i < _k; ++i) {
            result += (temp.get(i) + 1);
            if (i != _k - 1)
                result += ",";
        }
        return result;
    }

    public long getSize() {
        long size = 0;
        size = factorial(_n) / factorial(_n - _k) / factorial(_k);
        return size;
    }

    private long factorial(int n) {
        if (n == 0) {
            return 1;
        } else {
            return n * factorial(n - 1);
        }
    }

    private boolean isUniqueElement(int val[]) {
        java.util.Arrays.sort(val);
        int temp[] = new int[_k];
        for (int i = 0; i < _E.size(); ++i) {
            getElements(i, temp);
            java.util.Arrays.sort(temp);
            boolean match = true;
            for (int j = 0; j < temp.length; ++j) {
                if (val[j] != temp[j]) {
                    match = false;
                    break;// ほんのちょっと時間節約
                }
            }

            if (match == true)
                return false;
        }

        return true;
    }