CSES - Trailing Zeros
  • Time limit: 1.00 s
  • Memory limit: 512 MB

Your task is to calculate the number of trailing zeros in the factorial n!.

For example, 20!=2432902008176640000 and it has 4 trailing zeros.

Input

The only input line has an integer n.

Output

Print the number of trailing zeros in n!.

Constraints

  • 1 \le n \le 10^9

Example

Input:

20

Output:

4