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.io.DataInputStream;
import java.io.IOException;
import java.io.PrintStream;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.PriorityQueue;
import java.util.SortedMap;
import java.util.TreeMap;

public class Main {

	// invoked from main
	private void solve() throws Exception {
		int A = in.i();
		int P = in.i();
		out.println((3*A + P)/2);
	}


	public static void main(String[] args) throws Exception {
		instance.solve();
	}

	static PrintStream out = System.out;
	static FastReader in = new FastReader();
	static Main instance = new Main();
}

class FastReader {
	final private int BUF_SIZE = 1 << 16;
	private DataInputStream din = new DataInputStream(System.in);
	private byte[] buffer = new byte[BUF_SIZE];
	private int bufferPointer, bytesRead;

	String s() throws IOException {
		return s(64);
	}

	String s(int capacity) throws IOException {
		byte[] buf = new byte[capacity];
		int cnt = 0, c;
		while ((c = c()) != -1) {
			if (c == '\n') break;
			buf[cnt++] = (byte) c;
		}
		return new String(buf, 0, cnt);
	}

	int i() throws IOException {
		int ret = 0;
		byte c = c();
		while (c <= ' ') c = c();
		boolean neg = (c == '-');
		if (neg) c = c();
		do {
			ret = ret * 10 + c - '0';
		} while ((c = c()) >= '0' && c <= '9');
		return neg ? -ret : ret;
	}

	long l() throws IOException {
		long ret = 0;
		byte c = c();
		while (c <= ' ') c = c();
		boolean neg = (c == '-');
		if (neg) c = c();
		do {
			ret = ret * 10 + c - '0';
		} while ((c = c()) >= '0' && c <= '9');
		return neg ? -ret : ret;
	}

	double d() throws IOException {
		double ret = 0, div = 1;
		byte c = c();
		while (c <= ' ') c = c();
		boolean neg = (c == '-');
		if (neg) c = c();
		do {
			ret = ret * 10 + c - '0';
		} while ((c = c()) >= '0' && c <= '9');
		if (c == '.')
			while ((c = c()) >= '0' && c <= '9')
				ret += (c - '0') / (div *= 10);
		return neg ? -ret : ret;
	}

	private void fillBuffer() throws IOException {
		bytesRead = din.read(buffer, bufferPointer = 0, BUF_SIZE);
		if (bytesRead == -1) buffer[0] = -1;
	}

	byte c() throws IOException {
		if (bufferPointer == bytesRead) fillBuffer();
		return buffer[bufferPointer++];
	}
}