function main(input) {
    var args = input.split(' ');
    var apple = parseInt(args[0], 10);
    var spieces = parseInt(args[1], 10);
    var pieces;
    var pies;
  
    pieces = apple * 3;
    pieces += spieces;
    pies = pieces /  2;
    
    console.log('%d', pies);
  
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));