Sequence#575
Vasya has become interested in creating new sequences and studying them. This time, he wrote the following sequence on the board: 1 2 3 2 3 4 3 4 5 4 5 6 5 6 7 ... Vasya wants to know at which position the number appears for the first time in this sequence.
Write a program that answers his question.
You are given a natural number (1 \le k \le 100).
Output a single number — the position where the number appears for the first time. The elements of the sequence are numbered starting from one.
Example 1