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 Python (3.4.3) (judge verdict: Runtime Error)

import sys
n = int(input())
lst = list(map(int, input().split()))
res = 0
for p in range(200):
  for i in range(n):
    if lst[i] % 2 == 1:
      print(res)
      sys.exit()
  lst = [int(j / 2) for j in lst]
  res += 1