#include<stdio.h>
#include<ctype.h>
int main(){
    int N;
    scanf("Invalid input");
    if(N<=0 || N> 100)
    {
        printf("Invalid input");
        return 0;
        
    } 
    char arr[N];
    for(int i=0;i<n;i++)
    {
        scanf(" %c",&arr[i]);
    }
    int evenSum = 0, oddSum -0;
    char *ptr = arr;
    for(int i=0;i<N;i++)
    {
        printf("Invalid input");
        return 0;
    }
    if(*(ptr +i) %2 ==0) 
    evenSum += *(ptr + i);
    else
    oddSum += *(ptr + i);
    }
    int diff = evenSum - oddSum;
    if(diff < 0) diff = -diff;
    printf("%d",diff);
    return 0;
}