Easy Solution in Java .
IntuitionApproachComplexity
Time complexity: O(n) .

Space complexity: O(1) .
Code
# Intuition
<!-- Describe your first thoughts on how to solve this problem. -->

# Approach
<!-- 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;
        int age;
        for (int i = 0; i < details.length; i++) {
            age = 0;
            age = (details[i].charAt(11) - '0') * 10 + (details[i].charAt(12) - '0');//  subtraction of ascii values.
            if (age > 60) {
                count++;
            }
        }
        return count;
    }
}
```
['Java']