Question
Digit Charm
Bob is fascinated by numbers composed solely of the digits three and four.
He wants to identify the Nth number in this unique sequence. Your task is to find the Nth positive integer that Bob adores.
He wants to identify the Nth number in this unique sequence. Your task is to find the Nth positive integer that Bob adores.
Input
The first and only line of input contains a single integer N.
Output
The output should contain a single number, the Nth positive integer that Bob loves.
Example
Sample Input
1
Sample Output
3
Sample Input
3
Sample Output
33
Explanation
series is like 3, 4, 33, 34, 44, 333......
1
Sample Output
3
Sample Input
3
Sample Output
33
Explanation
series is like 3, 4, 33, 34, 44, 333......