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

class FastReader 
{ 
    BufferedReader br; 
    StringTokenizer st; 
    
    public FastReader() 
    { 
        br = new BufferedReader(new InputStreamReader(System.in)); 
    } 
    
    String next() 
    { 
        while (st == null || !st.hasMoreElements()) 
        { 
            try
            { 
                st = new StringTokenizer(br.readLine()); 
            } 
            catch (IOException  e) 
            { 
                e.printStackTrace(); 
            } 
        } 
        return st.nextToken(); 
    } 
    
    int nextInt() 
    { 
        return Integer.parseInt(next()); 
    } 
    
    long nextLong() 
    { 
        return Long.parseLong(next()); 
    } 
    
    double nextDouble() 
    { 
        return Double.parseDouble(next()); 
    } 
    
    String nextLine() 
    { 
          String str = ""; 
        try
        { 
            str = br.readLine(); 
        } 
        catch (IOException e) 
        { 
            e.printStackTrace(); 
        } 
        return str; 
    } 
} 

class Solution
{
    void solve()
    {
        FastReader sc = new FastReader();

        int A = sc.nextInt();
        int P = sc.nextInt();

        int p = 3*A + P;

        System.out.println(p/2);
    }
}
  
public class Main 
{ 
    public static void main(String[] args) 
    { 
        Solution ob = new Solution();

        ob.solve();
    } 
} 