P10250 [GESP Sample Problem Level 6] Going Down the Stairs

Related multiple-choice and true/false questions: .

Mischievous Xiao Ming found that when going down the stairs, each step can move down $1$ stair, $2$ stairs, or $3$ stairs. Now there are a total of $N$ stairs. Can you help Xiao Ming calculate how many different ways there are?

Input one line containing an integer $N$.

Output one line containing one integer representing the answer.

For all testdata, it is guaranteed that $1 \leq N \leq 60$. Translated by ChatGPT 5