Language C programming, just use library stdio.h only

Final Recursion

Jojo wants to give you the final challenge about recursion. Here is the function. Suppose that f(x) is a function which returns f(x 1) + 1 if x > 0, and returns 0 if x = 0. Given the input x, determine the value of f(x).

Format Input

A single line consists of an integer x.

Format Output

A single line consists of an integer which describes the value of f(x).

Constraints

0 x 109

Sample Input 1 (standard input)

3

Sample Output 1 (standard output)

3

Sample Input 2 (standard input)

0

Sample Output 2 (standard output)

0

Explanation

On the first sample, the value of f(3) is f(3) = f(2) + 1 = (f(1) + 1) + 1 = ((f(0) + 1) + 1) + 1 = ((0 + 1) + 1) + 1 = (1 + 1) + 1 = 2 + 1 = 3.