At Stepan's university, it was decided to hold a chess olympiad. To prepare properly, Stepan wanted to play some practice games with his neighbor Robert, whom everyone in their building jokingly called Fischer. Robert was a pretty good chess player and happily agreed to help Stepan.
In the first two games, Stepan lost, then played a draw, and then won. Robert then changed his opening, and Stepan lost again, drew, and then won. Robert changed his opening once more, and the pattern repeated: Stepan lost, then drew, and then won. In total, they played many games, and this sequence kept repeating: first Stepan lost, then he drew, then he won. Determine how many losses Stepan had in the first games.
The input consists of a single integer (0 \leq N \leq 10^{18}) — the number of games played.
Output a single integer — the number of losses Stepan had in the first games against Robert.
Example 1