Problem:
Score : 100 points

Problem Statement

Snuke has a grid consisting of three squares numbered 1, 2 and 3.
In each square, either 0 or 1 is written. The number written in Square i is s_i.

Snuke will place a marble on each square that says 1.
Find the number of squares on which Snuke will place a marble.

Constraints

Each of s_1, s_2 and s_3 is either 1 or 0.

Input

Input is given from Standard Input in the following format:

s_{1}s_{2}s_{3}

Output

Print the answer.

Sample Input 1

101

Sample Output 1

2

A marble will be placed on Square 1 and 3.

Sample Input 2

000

Sample Output 2

0

No marble will be placed on any square.

Solution in Fortran (gfortran v4.8.4) (judge verdict: Accepted)

module global_variables
end module global_variables
program main
  use global_variables
  implicit none
  integer i,res
  character(3) s
  read *, s
  res = 0
  do i=1,3
    if (s(i:i) .eq. '1') then
      res = res + 1
    endif
  enddo
  print '(i0)', res
end program main