s = input()

num_str_lst = [
    '1',
    '2',
    '3',
    '4',
    '5',
    '6',
    '7',
    '8',
    '9',
    '0',
]
ans = 0
for char in s:
    if char in num_str_lst:
        ans += int(char)

print(ans)