#include <stdio.h>
#include <stdio.h>
#include <ctype.h>
int main()
{
    int n;
    char arr[100];
    int evenSum = 0, oddSum = 0;
    scanf("%d", &n);
    if (n < 1 || n > 100)
    {
        printf("Invalid input\n");
        return 0;
    }
    for (int i = 0; i < n; i++)
    {
        scanf(" %c", &arr[i]);
        {
            if (!isalpha(arr[i]))
            {
                printf("Invalid input\n");
                return 0;
            }
        }
        char *ptr = arr;
        for (int i = 0; i < n; i++)
        {
            int ascii = (int)*(ptr + i);
            if (ascii % 2 == 0)
            evenSum += ascii;
            else
            oddSum += ascii;
        }
        printf("%d\n", abs(evenSum - oddSum));
    }
    return 0;
}