def compute_balance(n, initials):
    # Check for invalid n
    if n < 0:
        return "Invalid input"

    # Check if all initials are alphabetic
    for ch in initials:
        if not ch.isalpha():
            return "Invalid input"

    # Simulating pointer traversal using index reference
    even_sum = 0
    odd_sum = 0
    ptr = 0  # acts like a pointer

    while ptr < n:
        ascii_val = ord(initials[ptr])
        if ascii_val % 2 == 0:
            even_sum += ascii_val
        else:
            odd_sum += ascii_val
        ptr += 1  # move pointer

    return abs(even_sum - odd_sum)


# Driver code
try:
    n = int(input().strip())
    initials = input().strip().split()

    if len(initials) != n:
        print("Invalid input")
    else:
        result = compute_balance(n, initials)
        print(result)
except:
    print("Invalid input")