#977. 3-bonacci
The first 3 terms are 1, and each next term is the sum of the previous 3 terms. Find the n-th term.
### Input
One integer n (1 ≤ n ≤ 60).
### Output
A number.
Examples
Input
54
Output
46294000891609
Input
38
Output
2698569577
💡 You can solve it with Python, JavaScript or blocks. Read the input line by line with input(). Don't print a question (like input("Number: ")). Print exactly what the output asks for, nothing more.