str=gets.chomp

def is_number?(str1)
  return true if str1 == "0"
  return (str1.to_i > 0 and str1.to_i < 10)
end

def plusall(s1)
  total = 0
  for num in 0..s1.length
    if is_number?(s1[num, 1])
      total += s1[num, 1].to_i
    end
  end
  puts total
end

puts plusall(str)