'use strict'
function Main(input) {
  input = input.split(" "); 
  let apple = parseInt(input[0], 10);
  let piece = parseInt(input[1], 10);
  let sum = Math.floor((apple*3 + piece)/2);
  console.log('%s',sum);
}

Main(require("fs").readFileSync("/dev/stdin", "utf8"));
