Nth number made up of Prime digits only #GeeksForGeeks

Approach:

Approach: Starting from 2, keep checking if the number is made up of only Prime digits (2,3,5,7) and stop when nth such number is found.

Below is the implementation of the above approach:

Python Code:
def isPrime(n):

    for num in range(2, int(n ** 0.5) + 1):

        if n % num == 0:

            return False

    if n == 0 or n == 1:

        return False

    return True

def findNthprimeDigitNumber(n):

    count = 0

    i = 2

    lst = []

    while True:

        num = i

        k = str(num)

        isMadeOfprime = True

        while num >= 1:

            if (isPrime(int(num % 10))) == 0:

                isMadeOfprime = False

                break

            elif num < 2:

                isMadeOfprime = False

                break

            num /= 10

        if isMadeOfprime == True and isPrime(int(k[0])):

            count += 1

            lst.append(i)

        if count == n:

            # print(lst)

            return i

        i += 1

if __name__ == "__main__":

        print(findNthprimeDigitNumber(int(input())))