2678. Number of Senior Citizens

class Solution {
public:
    int countSeniors(vector<string>& details)
    {
        int cnt = 0;
        for (const auto& s : details)
        {
            int age = (s[11] - '0') * 10 + (s[12] - '0');
            if (age > 60) ++cnt;
        }
        return cnt;
    }
};

• T: $O(N)$
• S: $O(1)$