// editor1
#include<stdio.h>
#include<ctype.h>
#include<stdlib.h>
void main()
{
    int N;
    scanf("%d",&N);
    if(N<0)
    {
        printf("Invalid input");
    }
    char ch;
    int evenSum=0,oddSum=0;
    for(int i=0;i<N;i++)
    {
    scanf(" %c ",&ch);
    if(!isalpha(ch))
    {
        printf("Invalid input");
    }
    int ascii=(int)ch;
    if(ascii%2==0)
      evenSum+=ascii;
    else
      oddSum+=ascii;
    }
    int diff=abs(evenSum-oddSum);
    printf("%d",diff);
    }
}