#include <stdio.h>
#include <ctype.h>
#include <stdlib.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 = o; 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 + 1);
        if(ascii % 2 == 0)
        evenSum += ascii;
        else
        oddSum += ascii;
    }
    printf("%d\n",abs(evenSum - oddSum));
    retrurn 0;
}