< Back 1832. Check if the Sentence Is Pangram Not really a serious question, to be honest. A pangram is a sentence where every letter of the English alphabet appears at least once. We know the English alphabet has 26 letters, so we just declare the input string as a set and check to see if the length of the set is 26. The solution is as follows: class Solution: def checkIfPangram(self, sentence: str) -> bool: return len(set(sentence)) == 26 _ Time Complexity: O(1) - We know the English alphabet has 26 letters, so we know the set will have at most 26. _ Space Complexity: O(1) - The input string only consists of alphabet letters, so the set will have at most 26.