day4.dart

void main() {
  letters("Omol-=adefASAFads23");
}

letters(String letter) {
  letter = letter.replaceAll(new RegExp(r'[^a-zA-Z]'), '');
  var myList = letter.split("");
  int upper = 0;
  int lower = 0;
  for (var i = 0; i < myList.length; i++) {
    if (myList[i] == myList[i].toUpperCase()) {
      upper += 1;
    } else if (myList[i] == myList[i].toLowerCase()) {
      lower += 1;
    }
  }
  print("Upper Case Letters: $upper");
  print("Lower Case Letter: $lower");
}