function lookUp(firstName, prop){
// Only change code below this line
  var result;
  for (var x = 0; x < contacts.length; x++){
    if (contacts[x].firstName === firstName) {
        if (contacts[x][prop]) {
            return contacts[x][prop];
        } else {
            return "No such property";
        }
    }
  }
return "No such contact";
// Only change code above this line
}