Given a number 'N'. The task is to find the N^{th} number whose each digit is a prime number i.e 2, 3, 5, 7. In other words you have to find nth number of this sequence : 2, 3, 5, 7, 22, 23 ,.. and so on.
Example 1:
Input:
N = 10
Output: 33
Explanation:10^{th} number in the sequence of
numbers whose each digit is prime is 33.
Example 2:
Input:
N = 21
Output: 222
Explanation:21^{st} number in the sequence of
numbers whose each digit is prime is 222.
Your Task:
Complete primeDigits function and return the nth number of the given sequence made of prime digits.
Constraints:
1 <= N <= 100

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