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 Julia (0.5.0) (judge verdict: Accepted)

# AtCoder Beginner Contest 081 A
# [URL]      https://atcoder.jp/contests/abc081/tasks/abc081_a
# [compiler] Version 0.5.0
# [reference]
# <1> https://atcoder.jp/contests/abc081/submissions/3181551

#==================================================================================================#
function isTargetNum( char, target )
	return Base.ifelse( Base.isequal(char, target), 1, 0 )
end

function abc081_a()

	# STEP.01
	# get the target positive numbers
	buffer = Base.readline( Base.STDIN )

	# STEP.02
	# count up the target letter
	count =  Base.zero( Core.Int16 )
	count += Main.isTargetNum( buffer[1], '1' )
	count += Main.isTargetNum( buffer[2], '1' )
	count += Main.isTargetNum( buffer[3], '1' )

	# STEP.03
	# output the result
	Base.println( Base.STDOUT, count )

	# STEP.TRUE_END
	return Base.nothing

end

#==================================================================================================#

Main.abc081_a()