#include<stdio.h>
#include<ctype.h>
#include<stdlib.h>
int main()
{
    int N;
    scanf("%d",&N);
    if(N < 1 ||N > 100)
    {
        printf("Invalid Input");
        return 0;
    }
    char ch;
    int sumEven = 0,sumOdd = 0;
    for (int i = 0; i < N; i++)
    {
        scanf(" %c",&ch);
        if(!isalpha(ch))
        {
            printf("Invalid input");
            return 0;
        }
        int asciiValue = (int)ch;
        if(asciiValue % 2 == 0)
        sumEven +=asciiValue;
        else
        sumOdd +=asciiValue;
    }
    int diff = abd(sumEven - sumOdd);
    printf("%d",diff);
      return 0;
    }