function calculate(num1, num2){
  return num1.parseInt(2) + num2.parseInt(2);
}

String.prototype.parseInt = function (radix) {
  var result = 0;
  var pow = 1;

  for (var i = this.length - 1; i >= 0; i--) {
    result += +this[i] * pow;
    pow *= radix;
  }

  return result;
};