Problem:
Score : 500 points

Problem Statement

We have N locked treasure boxes, numbered 1 to N.

A shop sells M keys. The i-th key is sold for a_i yen (the currency of Japan), and it can unlock b_i of the boxes: Box c_{i1}, c_{i2}, ..., c_{i{b_i}}. Each key purchased can be used any number of times.

Find the minimum cost required to unlock all the treasure boxes. If it is impossible to unlock all of them, print -1.

Constraints

All values in input are integers.

1 \leq N \leq 12

1 \leq M \leq 10^3

1 \leq a_i \leq 10^5

1 \leq b_i \leq N

1 \leq c_{i1} < c_{i2} < ... < c_{i{b_i}} \leq N

Input

Input is given from Standard Input in the following format:

N M
a_1 b_1
c_{11} c_{12} ... c_{1{b_1}}
:
a_M b_M
c_{M1} c_{M2} ... c_{M{b_M}}

Output

Print the minimum cost required to unlock all the treasure boxes.
If it is impossible to unlock all of them, print -1.

Sample Input 1

2 3
10 1
1
15 1
2
30 2
1 2

Sample Output 1

25

We can unlock all the boxes by purchasing the first and second keys, at the cost of 25 yen, which is the minimum cost required.

Sample Input 2

12 1
100000 1
2

Sample Output 2

-1

We cannot unlock all the boxes.

Sample Input 3

4 6
67786 3
1 3 4
3497 1
2
44908 3
2 3 4
2156 3
2 3 4
26230 1
2
86918 1
3

Sample Output 3

69942

Solution in C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;

public class Program
{
    private int N;
    private int M;
    private int[] A, B;
    private int[] C;

    public void Solve()
    {
        var sc = new Scanner();
        N = sc.NextInt();
        M = sc.NextInt();
        A = new int[M];
        B = new int[M];
        C = new int[M];
        for (int i = 0; i < M; i++)
        {
            A[i] = sc.NextInt();
            B[i] = sc.NextInt();
            var c = sc.IntArray();
            int tmp = 0;
            for (int j = 0; j < B[i]; j++)
            {
                tmp |= 1 << (c[j] - 1);
            }

            C[i] = tmp;
        }

        int l = 1 << N;

        long[,] dp = new long[M + 1, l];
        for (int i = 0; i <= M; i++)
        {
            for (int j = 0; j < l; j++)
            {
                dp[i, j] = int.MaxValue;
            }
        }

        dp[0, 0] = 0;

        for (int i = 0; i < M; i++)
        {
            // i番目の鍵使わない
            for (int j = 0; j < l; j++)
            {
                if (dp[i, j] != int.MaxValue)
                {
                    dp[i + 1, j] = Math.Min(dp[i + 1, j], dp[i, j]);
                }
            }

            // 使う
            for (int j = 0; j < l; j++)
            {
                if (dp[i, j] != int.MaxValue)
                {
                    dp[i + 1, j | C[i]] = Math.Min(dp[i + 1, j | C[i]], dp[i, j] + A[i]);
                }
            }
        }

        if (dp[M, l - 1] == int.MaxValue)
        {
            Console.WriteLine(-1);
            return;
        }

        Console.WriteLine(dp[M, l - 1]);
    }

    public static void Main(string[] args)
    {
        new Program().Solve();
    }
}

#region GCD LCM

/// <summary>
/// 様々な数学的関数の静的メソッドを提供します．
/// </summary>
public static partial class MathEx
{
    /// <summary>
    /// 2 つの整数の最大公約数を求めます．
    /// </summary>
    /// <param name="n">最初の値</param>
    /// <param name="m">2 番目の値</param>
    /// <returns>2 つの整数の最大公約数</returns>
    /// <remarks>ユークリッドの互除法に基づき最悪計算量 O(log N) で実行されます．</remarks>
    public static int GCD(int n, int m)
    {
        return (int) GCD((long) n, m);
    }


    /// <summary>
    /// 2 つの整数の最大公約数を求めます．
    /// </summary>
    /// <param name="n">最初の値</param>
    /// <param name="m">2 番目の値</param>
    /// <returns>2 つの整数の最大公約数</returns>
    /// <remarks>ユークリッドの互除法に基づき最悪計算量 O(log N) で実行されます．</remarks>
    public static long GCD(long n, long m)
    {
        n = Math.Abs(n);
        m = Math.Abs(m);
        while (n != 0)
        {
            m %= n;
            if (m == 0) return n;
            n %= m;
        }

        return m;
    }


    /// <summary>
    /// 2 つの整数の最小公倍数を求めます．
    /// </summary>
    /// <param name="n">最初の値</param>
    /// <param name="m">2 番目の値</param>
    /// <returns>2 つの整数の最小公倍数</returns>
    /// <remarks>最悪計算量 O(log N) で実行されます．</remarks>
    public static long LCM(long n, long m)
    {
        return (n / GCD(n, m)) * m;
    }
}

#endregion

#region PrimeSieve

public static partial class MathEx
{
    /// <summary>
    /// ある値までに素数表を構築します．
    /// </summary>
    /// <param name="max">最大の値</param>
    /// <param name="primes">素数のみを入れた数列が返される</param>
    /// <returns>0 から max までの素数表</returns>
    /// <remarks>エラトステネスの篩に基づき，最悪計算量 O(N loglog N) で実行されます．</remarks>
    public static bool[] Sieve(int max, List<int> primes = null)
    {
        var isPrime = new bool[max + 1];
        for (int i = 2; i < isPrime.Length; i++) isPrime[i] = true;
        for (int i = 2; i * i <= max; i++)
            if (!isPrime[i]) continue;
            else
                for (int j = i * i; j <= max; j += i)
                    isPrime[j] = false;
        if (primes != null)
            for (int i = 0; i <= max; i++)
                if (isPrime[i])
                    primes.Add(i);

        return isPrime;
    }
}

#endregion

class Scanner
{
    public Scanner()
    {
        _pos = 0;
        _line = new string[0];
    }

    const char Separator = ' ';
    private int _pos;
    private string[] _line;

    #region スペース区切りで取得

    public string Next()
    {
        if (_pos >= _line.Length)
        {
            _line = Console.ReadLine().Split(Separator);
            _pos = 0;
        }

        return _line[_pos++];
    }

    public int NextInt()
    {
        return int.Parse(Next());
    }

    public long NextLong()
    {
        return long.Parse(Next());
    }

    public double NextDouble()
    {
        return double.Parse(Next());
    }

    #endregion

    #region 型変換

    private int[] ToIntArray(string[] array)
    {
        var result = new int[array.Length];
        for (int i = 0; i < array.Length; i++)
        {
            result[i] = int.Parse(array[i]);
        }

        return result;
    }

    private long[] ToLongArray(string[] array)
    {
        var result = new long[array.Length];
        for (int i = 0; i < array.Length; i++)
        {
            result[i] = long.Parse(array[i]);
        }

        return result;
    }

    private double[] ToDoubleArray(string[] array)
    {
        var result = new double[array.Length];
        for (int i = 0; i < array.Length; i++)
        {
            result[i] = double.Parse(array[i]);
        }

        return result;
    }

    #endregion

    #region 配列取得

    public string[] Array()
    {
        if (_pos >= _line.Length)
            _line = Console.ReadLine().Split(Separator);

        _pos = _line.Length;
        return _line;
    }

    public int[] IntArray()
    {
        return ToIntArray(Array());
    }

    public long[] LongArray()
    {
        return ToLongArray(Array());
    }

    public double[] DoubleArray()
    {
        return ToDoubleArray(Array());
    }

    #endregion
}