#include <stdio.h>
#include <ctype.h>
#include <stdlib.h>

int calculateHarmony(char *arr, int n) {
    int evenSum = 0, oddSum = 0;
    for (int i = 0; i < n; i++) {
        if (!isalpha(*(arr + i))) {
            return -1; 
        }
        int ascii = *(arr + i);
        if (ascii % 2 == 0)
            evenSum += ascii;
        else
            oddSum += ascii;
    }
    return abs(evenSum - oddSum);
}

int main() {
    int n;
    scanf("%d", &n);
    if (n < 0) {
        printf("Invalid input\n");
        return 0;
    }

    char initials[n];
    for (int i = 0; i < n; i++)
        scanf(" %c", initials + i);

    int result = calculateHarmony(initials, n);
    if (result == -1)
        printf("Invalid input\n");
    else
        printf("%d\n", result);

    return 0;
}#include <stdio.h>
#include <ctype.h>
#include <stdlib.h>

int calculateHarmony(char *arr, int n) {
    int evenSum = 0, oddSum = 0;
    for (int i = 0; i < n; i++) {
        if (!isalpha(*(arr + i))) {
            return -1; 
        }
        int ascii = *(arr + i);
        if (ascii % 2 == 0)
            evenSum += ascii;
        else
            oddSum += ascii;
    }
    return abs(evenSum - oddSum);
}

int main() {
    int n;
    scanf("%d", &n);
    if (n < 0) {
        printf("Invalid input\n");
        return 0;
    }

    char initials[n];
    for (int i = 0; i < n; i++)
        scanf(" %c", initials + i);

    int result = calculateHarmony(initials, n);
    if (result == -1)
        printf("Invalid input\n");
    else
        printf("%d\n", result);

    return 0;
}