class Solution {
    public boolean squareIsWhite(String coordinates) {
        char letter = coordinates.charAt(0);
        int digit = coordinates.charAt(1) - '0';
        
        if (letter == 'a' || letter == 'c' || letter == 'e' || letter == 'g') { 
            return digit % 2 == 0; // when digit is even
        } else { 
            return digit % 2 == 1; // when digit is odd
        }
    }
}