Answer using Integer.parseInt
Complexity
Time complexity: O(n)

Space complexity: O(1)
Code

<!-- Describe your approach to solving the problem. -->

# Complexity
- Time complexity: ***O(n)***
<!-- Add your time complexity here, e.g. $$O(n)$$ -->

- Space complexity: ***O(1)***
<!-- Add your space complexity here, e.g. $$O(n)$$ -->

# Code
```java []
class Solution {
    public int countSeniors(String[] details) {
        int count = 0;

        for(int i=0; i<details.length; i++){
            int age = Integer.parseInt(details[i].substring(11, 13));

            if(age > 60){
                count++;
            }
        }
        return count;
    }
}
```
['Array', 'String', 'Java']