Python 3   ||   1 line,  string comparison   ||   T/S: 99%  /  97%
\nclass Solution:\n    def countSeniors(self, details: List[str]) -> int:\n\n        return sum(d[11:13] > \'60\' for d in details)\n\n\nhttps://leetcode.com/pr
```\nclass Solution:\n    def countSeniors(self, details: List[str]) -> int:\n\n        return sum(d[11:13] > \'60\' for d in details)\n\n```\n[https://leetcode.com/problems/number-of-senior-citizens/submissions/1340099828/](https://leetcode.com/problems/number-of-senior-citizens/submissions/1340099828/)\n\nI could be wrong, but I think that time complexity is *O*(*N*) and space complexity is *O*(1), in which *N* ~ `len(nums)`.\n
['Python3']