#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 = 0; i<n; i++) {
        sacnf(" %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 (asii %2 == 0)
            evensum += ascii;
         else
             oddSum +=ascii;
     }
     
     printf("%d\n",abs(evenSum - oddSum));
     
     return 0;
}