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.Generic;
using System.IO;
using System.Text;
class ChokudaiSpeedRun002 {
    static int __cnt = 0;
#if LOCAL_ENVIRONMENT
    static string __mark = "@@@";
#endif
    static void Main(string[] args) {
#if LOCAL_ENVIRONMENT
        StreamReader __sr = new StreamReader("stdin.txt");
        string __str = __sr.ReadToEnd();
        __sr.Close();
        int __index = __str.IndexOf(__mark, 0);
        while (__index != -1) {
            __index = __str.IndexOf(__mark, __index + __mark.Length);
            __cnt++;
        }
        if (__cnt > 0) {
            Console.Write("Eenter test data no(1-{0})? ", __cnt);
            Console.Out.Flush();
            if (!int.TryParse(Console.ReadLine(), out __cnt)) __cnt = 1;
            Console.WriteLine("Select/Default test data: {0}", __cnt);
        }
        var stdin = new System.IO.StreamReader("stdin.txt");
        Console.SetIn(stdin);
#endif
        SimpleScanner sc = new SimpleScanner(__cnt);
        int A = sc.NextInt(), B = sc.NextInt();
        int ans = (A*3 + B) / 2;
        Console.WriteLine(ans);
    } //Main

    public static int LowerBound<T>(T[] array, int start, int end, T value, IComparer<T> comparer) {
        int low = start, high = end, mid;
        while (low < high) {
            mid = ((high - low) >> 1) + low;
            if (comparer.Compare(array[mid], value) < 0)
                low = mid + 1;
            else
                high = mid;
        }
#if LOCAL_ENVIRONMENT
        Console.Error.WriteLine($"LowerBound(array:{array.ToStringA()}");
        Console.Error.WriteLine($"LowerBound(start:{start}, end:{end}, value:{value.ToString()}) return:{low}");
#endif
        return low;
    }
    public static int LowerBound<T>(T[] array, T value) where T : IComparable {
        return LowerBound(array, 0, array.Length, value, Comparer<T>.Default);
    }

    public class BIT {
        int n;
        int[] data;
        public BIT(int size){
            n = size + 1;
            data = new int[n];
        }
        public void add(int i, int x) {
            while (i < n) {
                data[i] += x;
                i += i & -i;
            }
        }
        public int sum(int i) {
            int ret = 0;
            while (i > 0) {
                ret += data[i];
                i -= i & -i;
            }
            return ret;
        }
    }

    public class Item : IEquatable<Item>, IComparable<Item> {
        public long value1 { get; set; }
        public long value2 { get; set; }
        public Item(long value1, long value2) {
            this.value1 = value1;
            this.value2 = value2;
        }
        public override string ToString() {
            return $"[value1:{this.value1}, value2:{this.value2}]";
        }
        public bool Equals(Item other) {
            if (other == null) return false;
            return this.value1 == other.value1 && this.value2 == other.value2;
        }
        public override bool Equals(Object obj) {
            if (obj == null) return false;
            Item item = obj as Item;
            if (item == null)  return false;
            else return Equals(item);
        }
        public override int GetHashCode() {
            long hc = this.value1 * this.value2;
            return hc.GetHashCode();
        }
        public int CompareTo(Item other) {
            if (other == null) return -1;
            if (this.value1 == other.value1)
                return this.value2.CompareTo(other.value2);
            else
                return this.value1.CompareTo(other.value1);
        }
        public int Compare(Item x, Item y) {
            if (x == null) return 1;
            else return x.CompareTo(y);

        }
    }

    public class SimpleScanner {
        private int cnt;
        private string[] items;
        public SimpleScanner(int cnt = 0) {
            this.cnt = 0;
            var sb = new StringBuilder();
            var s = Console.ReadLine();
            while (s != null) {
                sb.Append(s + " ");
                s = Console.ReadLine();
            }
            this.items = sb.ToString().Split(' ');
#if LOCAL_ENVIRONMENT
            if (cnt > 0) {
                int index = Array.IndexOf(this.items, __mark + cnt.ToString());
                this.cnt = index + 1;
            }
            Console.Error.WriteLine("SimpleScanner.cnt: {0}", this.cnt);
            Console.Error.WriteLine("SimpleScanner.items: {0}", this.items.ToStringA());
#endif
        }
        public void SetCnt(int n) { this.cnt = n; }
        public int NextInt() {
            return int.Parse(this.items[this.cnt++]);
        }
        public long NextLong() {
            return long.Parse(this.items[this.cnt++]);
        }
        public string NextString() {
            return this.items[this.cnt++];
        }
        public int[] NextIntArray(int n) {
            if (n < 1) throw new IndexOutOfRangeException("引数は1以上であること！");
            var result = new int[n];
            for (var i = 0; i < n; i++) result[i] = this.NextInt();
#if LOCAL_ENVIRONMENT
            Console.Error.WriteLine("{0}", result.ToStringA());
#endif
            return result;
        }
        public long[] NextLongArray(int n) {
            if (n < 1) throw new IndexOutOfRangeException("引数は1以上であること！");
            var result = new long[n];
            for (var i = 0; i < n; i++) result[i] = this.NextLong();
#if LOCAL_ENVIRONMENT
            Console.Error.WriteLine("{0}", result.ToStringA());
#endif
            return result;
        }
        public string[] NextStringArray(int n) {
            if (n < 1) throw new IndexOutOfRangeException("引数は1以上であること！");
            var result = new string[n];
            for (var i = 0; i < n; i++) result[i] = this.NextString();
#if LOCAL_ENVIRONMENT
            Console.Error.WriteLine("{0}", result.ToStringA());
#endif
            return result;
        }
        public int[][] NextInt2Col(int n) {
            const int M = 2;
            if (n < 1) throw new IndexOutOfRangeException("引数は1以上であること！");
            int[][] result = new int[M][] {
                new int[n],
                new int[n],
            };
            for (var i = 0; i < n; i++) {
                result[0][i] = this.NextInt();
                result[1][i] = this.NextInt();
            }
#if LOCAL_ENVIRONMENT
            Console.Error.WriteLine("NextInt2Col: [");
            for (var i = 0; i < M; i++)
                Console.Error.WriteLine("  {0},", result[i].ToStringA());
            Console.Error.WriteLine("]");
#endif
            return result;
        }
    }

}
static class Extensions {
    public static string ToStringA<T>(this T[] array, string separator = ", ", string braces = "[]") {
        string bL = braces.Length > 0 ? braces[0].ToString() : "";
        string bR = braces.Length > 1 ? braces[1].ToString() : "";
        return bL + String.Join(separator, array) + bR;
    }
}