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: Accepted)

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using static System.Console;
using static System.Math;
 
public class Hello{
    public static void Main(){
        int[] read= inta();
        int total = read[0]*3 + read[1];
        WriteLine(total/2);
    
    }
    //各種読取
    static string rstr(){
        return ReadLine();
    }
    static int rint(){
        return int.Parse(ReadLine());
    }
    static long rlong(){
        return long.Parse(ReadLine());
    }
    static string[] stra(){
        return ReadLine().Split(' ');
    }
    static int[] inta(){
        string[] read_str_array = ReadLine().Split(' ');
        int[] return_int_array = new int[read_str_array.Length];
        for(int countup_i=0;countup_i<read_str_array.Length;countup_i++){
            return_int_array[countup_i] = int.Parse(read_str_array[countup_i]);
        }
        return return_int_array;
    }
    static int[,] inta2(int num_array,int in_array){
        int[,] int_array2 = new int[num_array,in_array];
        for(int i=0;i<num_array;i++){
            int[] temp_array = inta();
            for(int j=0;j<in_array;j++){
                int_array2[i,j] = temp_array[j];
            }
        }
        return int_array2;
    }
    static long[] longa(){
        string[] read_str_array = ReadLine().Split(' ');
        long[] return_long_array = new long[read_str_array.Length];
        for(long countup_i=0;countup_i<read_str_array.Length;countup_i++){
            return_long_array[countup_i] = long.Parse(read_str_array[countup_i]);
        }
        return return_long_array;
    }
    static double[] doublea(){
        string[] read_str_array = ReadLine().Split(' ');
        double[] return_double_array = new double[read_str_array.Length];
        for(long countup_i=0;countup_i<read_str_array.Length;countup_i++){
            return_double_array[countup_i] = long.Parse(read_str_array[countup_i]);
        }
        return return_double_array;
    }
    // A/B小数点以下切上
    static long divideup(long divided,long divid){
        long temp_divide = divided/divid;
        if(divided % divid > 0){
            temp_divide++;
        }
        return temp_divide;
    }
    static long GCD(long a,long b){
        if(a < b){
            long temp = a;
            a = b;
            b = temp;
        }
        if(a % b == 0){ return b; }
        else{
            long temp = b;
            b = a%b;
            a = temp;
            return GCD(a,b);
        }
    }
    static long LCM(long a,long b){
        return a * b / GCD(a,b);
    }
}
//知見
// (string) hogestr -> (char[]) hoge
    // char hoge = hogestr.ToCharArray();
// (char[]) hoge -> (string) hogestr
    // string hoge = new string(hoge);
// Hashtable ×  Dictionary ○
// Dictionary hoge<string,int>
    // hoge.ContainsKey(string) -> return boolean
    // hoge[string] -> return int
    // hoge[int] -> CE
// Dictionary hoge<int1,int2>
    // hoge<int1,int2>: hoge[int1] -> return int2
    // KeyValuePair<int,int> k <-> k.Key == int1 / k.Value == int2
// SortedDictionary() > SortedList() ???
// キュー　-> 幅優先 ???
// スタック -> 深さ優先 ???