Problem:
Sum of Numbers

Write a program which reads an integer and prints sum of its digits.

Input

The input consists of multiple datasets. For each dataset, an integer x is given in a line. The number of digits in x does not exceed 1000.

The input ends with a line including single zero. Your program should not process for this terminal symbol.

Output

For each dataset, print the sum of digits in x.

Sample Input

123
55
1000
0

Sample Output

6
10
1

Solution in Ruby (judge verdict: Accepted)

def f(n)
  if n < 10
    return n
  else
    return n % 10 + f(n / 10)
  end
end
while (x = gets.to_i) != 0
  puts f(x)
end