Score : $300$ points
Snuke has decided to play with a six-sided die. Each of its six sides shows an integer $1$ through $6$, and two numbers on opposite sides always add up to $7$.
Snuke will first put the die on the table with an arbitrary side facing upward, then repeatedly perform the following operation:
For example, let us consider the situation where the side showing $1$ faces upward, the near side shows $5$ and the right side shows $4$, as illustrated in the figure. If the die is rotated toward the right as shown in the figure, the side showing $3$ will face upward. Besides, the side showing $4$ will face upward if the die is rotated toward the left, the side showing $2$ will face upward if the die is rotated toward the front, and the side showing $5$ will face upward if the die is rotated toward the back.
Find the minimum number of operation Snuke needs to perform in order to score at least $x$ points in total.
The input is given from Standard Input in the following format:
Print the answer.