The bee can go in honeycomb as shown in the figure --- with moves $1$ and $2$ from upper row and with move $3$ from the lower. \includegraphics{https://static.e-olymp.com/content/44/444be65c2ca0ec12efbd13c7c7cde85f292e12a6.jpg} \InputFile The number of hexagons $n~(1 \le n \le 45)$ in the upper row. The lower row contains $1$ hexagon less. \OutputFile Print the number of ways to get from the first cell of the top row to the last cell of the same row.