// editor1
#include <stdio.h>
#include <ctype.h>
#include <stdlib.h>
#include <math.h>
int main() {
    int n;
    scanf("%d", &n);
    if (n < 1 || n > 100) {
        printf("Invalid input\n");
        return 0;
    }
    char initials[101];
    int evenSum = 0, oddSum = 0;
    for (int i = 0; i < n; i++) {
        scanf(" %c", &initials[i]);
idate character
        if (!isalpha(initials[i])) {
            printf("Invalid input\n");
            return 0;
        }
    }

    char *ptr = initials;

    for (int i = 0; i < n; i++, ptr++) {
        int ascii = (int)(*ptr);
        if (ascii % 2 == 0)
            evenSum += ascii;
        else
            oddSum += ascii;
    }

    int diff = abs(evenSum - oddSum);
    printf("%d\n", diff);

    return 0;
}