/******************************************************************************

                            Online C Compiler.
                Code, Compile, Run and Debug C program online.
Write your code in this editor and press "Run" button to compile and execute it.

*******************************************************************************/

#include <stdio.h>

int main()
{
    int n,m;
    scanf("%d %d",&n,&m);
    m = n*3 + m;
    printf("%d",m/2);

    return 0;
}
