D. District 42
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output

In the mystical land of District 42, where life, the universe, and everything is just a little bit odd, residents ponder a curious question. They observe the sequence of numbers $$$1, 2, 3, \dots, n$$$ without leading zeros or commas. Their quest is to determine how many times the mystical number $$$42$$$ appears within this sequence.

Input

The only line of the input contains a single integer $$$n$$$ ($$$1 \leq n \leq 2 \cdot 10^5$$$), the length of the sequence.

Output

Print one integer — number of times $$$42$$$ appears.

Examples
Input
24
Output
0
Input
25
Output
1
Input
250
Output
9
Note

In the second example, the sequence is $$$1234567891011\dots2{\bf 42}5$$$, at which point $$$42$$$ appears for the first time.