import java.util.Scanner;

public class temp {
	public static void main(String[] args) {
		Scanner input = new Scanner(System.in);
		String line = input.nextLine();
		String[] linesplit = line.split(" ");

		double sum =0;

		for (int i = 0; i < linesplit.length; i++) {
			double number=0;
				char first;
				char last;
				int possitonA;
			 first = linesplit[i].charAt(0);
			 last = linesplit[i].charAt(linesplit[i].length()-1);
			 String insideNum = linesplit[i].substring(1, linesplit[i].length()-1);
			 number = Double.parseDouble(insideNum);
			 //beforeNumber
			 if (Character.isUpperCase(first)){
				 possitonA = first-'A'+1;
				number/=possitonA;
			 }
			 else {
				 possitonA = first-'a'+1;
				 number*=possitonA;
			}
			 if (Character.isUpperCase(last)){
				 possitonA = last-'A'+1;
				number-=possitonA;
			 }
			 else {
				 possitonA = last-'a'+1;
				 number+=possitonA;
			}
			sum+=number;
		}


	System.out.printf("%.2f",sum);



	}
}