function Main(input){
var A = input.split(" ")[0];
A = parseInt(A,10);
var P = input.split(" ")[1];
P = parseInt(P,10);

var p = A * 3 + P;
var pie = p / 2;
pie = Math.floor(pie);
console.log(pie);




    
}





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