Problem:
Score : 100 points

Problem Statement

We have A apples and P pieces of apple.

We can cut an apple into three pieces of apple, and make one apple pie by simmering two pieces of apple in a pan.

Find the maximum number of apple pies we can make with what we have now.

Constraints

All values in input are integers.

0 \leq A, P \leq 100

Input

Input is given from Standard Input in the following format:

A P

Output

Print the maximum number of apple pies we can make with what we have.

Sample Input 1

1 3

Sample Output 1

3

We can first make one apple pie by simmering two of the three pieces of apple. Then, we can make two more by simmering the remaining piece and three more pieces obtained by cutting the whole apple.

Sample Input 2

0 1

Sample Output 2

0

We cannot make an apple pie in this case, unfortunately.

Sample Input 3

32 21

Sample Output 3

58

Solution in C# (Mono 4.6.2.0) (judge verdict: Runtime Error)

using System;
using System.Collections.Generic;
using System.Text;

namespace ConsoleApplication1
{
	class Program
	{
		static void Main(string[] args)
		{
			var input = Console.ReadLine().Split(' ');
			int n = int.Parse(input[0]);    // スイッチの数
			int m = int.Parse(input[1]);    // 電球の数

			var lights = new List<Light>(m);
			for (int i = 0; i < m; i++)
			{
				var arg = Console.ReadLine();
				lights.Add(new Light(n, arg));
			}
			var rems = Console.ReadLine().Split(' ');
			for (int i = 0; i < m; i++)
			{
				lights[i].SetRemainder(int.Parse(rems[i]));
			}

			int maxSwitchPattern = (int)Math.Pow(2, n) - 1;
			int countAllLightOn = 0;
			for (int i = 0; i <= maxSwitchPattern; i++)
			{
				bool isLightOn = true;
				// 各電球について確認
				for (int j = 0; j < m; j++)
				{
					if (!lights[j].IsLightOn(i))
					{
						isLightOn = false;
						break;
					}
				}
				if (isLightOn)
				{
					countAllLightOn++;
				}
			}

			Console.WriteLine(countAllLightOn);
		}

		public class Light
		{
			int mTotalSw = 0;
			int mRemainder = 0;
			int mSwitch = 0;

			public Light(int totalSw, string input)
			{
				mTotalSw = totalSw;
				var args = input.Split(' ');
				int switchCount = int.Parse(args[0]);
				var switchIndex = new List<int>(switchCount);
				for (int i = 0; i < switchCount; i++)
				{
					switchIndex.Add(int.Parse(args[i + 1]) - 1);
				}
				for (int i = 0; i < mTotalSw; i++)
				{
					mSwitch <<= 1;
					if (switchIndex.Contains(i))
					{
						mSwitch |= 1;
					}
				}
			}

			public void SetRemainder(int remainder)
			{
				mRemainder = remainder;
			}

			public bool IsLightOn(int switchState)  // switchState : N(<=10)ビットの整数. S1, S2, .... SN の状態を表すもの。ON ならビットを立てる
			{
				if (switchState == 0)
				{
					return false;    // 全てOFFの場合は余りの数に関係なく非点灯？
				}
				var state = switchState & mSwitch;   // 関連づいていてONになっているビットが立つ
				int onSwitchCount = 0;
				for (int i = 0; i < mTotalSw; i++)
				{
					if ((state & 1) == 1)
					{
						onSwitchCount++;
					}
					state >>= 1;
				}

				return (onSwitchCount % 2 == mRemainder);
			}
		}
	}
}