Problem Description

When a citizen of Pakken learns important information, exactly 1 minute later, they gather 5 citizens who have not yet received the information and simultaneously share the important information with them.

Pakken-kun, a citizen of Pakken, has obtained important information. He is the first citizen to have received this information.

After $ N $ minutes from when Pakken-kun obtained the information, what is the maximum number of citizens who will have received the information? This count includes citizens who receive the information exactly $ N $ minutes after Pakken-kun. Assume there are enough citizens to facilitate this process.

Input Format

The input is given from the standard input in the following format:

$ N $

Output Format

Output an integer representing the number of citizens who will have received the information after $ N $ minutes.

Sample Input and Output

Sample Input #1

1

Sample Output #1

6

Sample Input #2

2

Sample Output #2

31

Sample Input #3

7

Sample Output #3

97656

Notes/Hints

Constraints

• $1 \leq N \leq 20$.
• $ N $ is an integer.

Partial Points

This problem is divided into several sub-tasks, and you are considered to have solved a sub-task if you correctly answer all test cases for that sub-task. The score for your submission will be the sum of the points for the sub-tasks you solve.

1. (50 points) $ N = 1 $.
2. (50 points) No additional constraints.

Sample Explanation 1

After 1 minute, Pakken-kun and the 5 citizens he informed, totaling 6 citizens, have received the important information.

Sample Explanation 2

After 1 minute, 5 new citizens receive the information. After 2 minutes, 25 new citizens receive the information. In total, 1 + 5 + 25 = 31 citizens have received the information.

见题面 Input 部分

见题面 Output 部分