Make Him Happy

In Chef's house there are N apples lying in a row on the floor. These apples are numbered from 1 (left most one) to N (right most one). The types of apples are also numbered by positive integers, and the type of apple i is Ti. Chef has recently brought two trained dogs. Both of the dogs are too intelligent to know the smell of each type of apple. If Chef gives a dog an integer x, and releases it