1058: Climb the stair version 2
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Description
Given a staircase with N steps, a child runs up the stair with either 1, 2 or 3 steps at a time. How many possible different ways for the child reach the Nth stair but only with one jump is 3 steps.
Input
One integer which is the ways
$ 1 \leq N \leq 20 $
$ 1 \leq N \leq 20 $
Output
One integer which is the number of ways
Sample Input Copy
4
Sample Output Copy
2