n = int(input())
if n < 0:
    print("Invalid input")
    exit()

chars = input().split()
if len(chars) != n:
    print("Invalid input")
    exit()

sum_even = 0
sum_odd = 0

for ch in chars:
    if len(ch) != 1 or not ch.isalpha():
        print("Invalid input")
        exit()
    ascii_val = ord(ch)
    if ascii_val % 2 == 0:
        sum_even += ascii_val
    else:
        sum_odd += ascii_val

print(abs(sum_even - sum_odd))