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)

program tenquestiontwo
 implicit none
 character(3) s
 integer i, n, res
 res = 0
 read(*,*) s
  do 10 i = 1,3
  read(s(i:i),*) n
   if (n.EQ.1) then
   res = res + 1
   end if
  10 continue
 write(*,*) res 
end program