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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.*;
import java.io.*;

public class Main {

    static BufferedReader br;
    static StringTokenizer st;

    public static void main(final String[] args) {
        br = new BufferedReader(new InputStreamReader(System.in));

        try {
            final int A = readInt();
            final int P = readInt();

            final Solver solver = new Solver();

            System.out.println(solver.solve(A, P));

        } catch (final IOException e) {
            e.printStackTrace();
        }
    }

    static String next() throws IOException {
        while (st == null || !st.hasMoreTokens())
            st = new StringTokenizer(br.readLine().trim());
        return st.nextToken();
    }

    static long readLong() throws IOException {
        return Long.parseLong(next());
    }

    static int readInt() throws IOException {
        return Integer.parseInt(next());
    }

    static double readDouble() throws IOException {
        return Double.parseDouble(next());
    }

    static char readCharacter() throws IOException {
        return next().charAt(0);
    }

    static String readLine() throws IOException {
        return br.readLine().trim();
    }
}

class Solver {
    public int solve(final int A, final int P) {
        final int pieces = A * 3 + P;

        return pieces / 2;
    }
}