Input : GeeksforGeeks
Output : No. of vowels : 5

Input : Hello World
Output : No. of vowels :  3

1. Create a set of vowels using set() and initialize a count variable to 0.
2. Traverse through the alphabets in the string and check if the letter in the string is present in set vowel.
3. If it is present, the vowel count is incremented.

Python Programming Tutorial | Count number of vowels using sets in given string: https://www.geeksforgeeks.org/python-program-count-number-vowels-using-sets-given-string/