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 (Python):
if __name__ == '__main__':
    area = input()
    print(area.count('1'))

Solution (Python):
s = input()
sc = s.count('1')
print(sc)

Solution (Python):
if __name__ == '__main__':

    s = input()
    target = '1'
    count = 0

    for i in s:
        if i == target:
            count = count + 1

    print(count)

Solution (Python):
S = input()
print(S.count('1'))

Solution (Python):
a = input()

c = a.count('1')

print(c)

Solution (Python):
print(input().count("1"))

Solution (Python):
input = str(input())
num = 0

for i in input:
  if i == "1":
    num += 1
    
print(num)

Solution (Python):
x = int(input())
ans = 0
if x//100==1:
    ans+=1
if x%100//10==1:
    ans+=1
if x%10//1 == 1:
    ans+=1
print(ans)

Solution (Python):
print(sum(list(map(int,list(input())))))

Solution (Python):
digits = list(input(''))
count = 0
if digits[0] == '1':
  count += 1
if digits[1] == '1':
  count += 1
if digits[2] == '1':
  count += 1
print(count)

Solution (Python):
print(input().count('1'))

Solution (Python):
n = 0
for s in input():
  if s == '1':
    n += 1
print(n)

Solution (Python):
s=list(input())
print(s.count("1"))

Solution (Python):
s = input()
print(int(s[0])+int(s[1])+int(s[2]))

Solution (Python):
s = input()
c=0
for i in s:
    if i == "1":
        c = c + 1
    else:
        pass
print(c)

Solution (Python):
print(sum([int(i) for i in input()]))

Solution (Python):
s = list(input())
print(s.count("1"))

Solution (Python):
s = list(input())
print(s.count("1"))

Solution (Python):
s = input()
n = 0
if s[0] == '1':
  n = n + 1
if s[1] == '1':
  n = n + 1
if s[2] == '1':
  n = n + 1
print (n)

Solution (Python):
s = input()
s1 = s[0]
s2 = s[1]
s3 = s[2]
n = 0
if s1 == '1':
  n = n + 1
if s2 == '1':
  n = n + 1
if s3 == '1':
  n = n + 1
print (n)

Solution (Python):
a,b,c = map(int, list(input()))
print(a+b+c)

Solution (Python):
A = list(input())

print(A.count("1"))

Solution (Python):
s = input()
counter = 0

if s[0] == '1' :
    counter += 1
if s[1] == '1' :
    counter += 1
if s[2] == '1' :
    counter += 1

print(counter)

Solution (Python):
s = input()
counter = 0

if s[0] == '1':
    counter += 1
if s[1] == '1':
    counter += 1
if s[2] == '1':
    counter += 1

print(counter)

Solution (Python):
s = input()



counter_b = 0
for i in range(0, len(s)):
    if s[i] ==  '1':
        counter_b+=1

print(counter_b)

Solution (Python):
s = input()



counter_a = 0

if s[0] == '1':
    counter_a+=1
if s[1] == '1':
    counter_a+=1
if s[2] == '1':
    counter_a+=1
print(counter_a)

Solution (Python):
s = input()
a = int(s[0])
b = int(s[1])
c = int(s[2])
count = 0


if a == 1:
    count += 1
if b == 1:
    count += 1
if c == 1:
    count += 1

print(count)

Solution (Python):


s = list(input())

s1 = int(s[0])
s2 = int(s[1])
s3 = int(s[2])

print(s1+s2+s3)

Solution (Python):
N = list(input())
print(N.count('1'))

Solution (Python):
N = list(input())
print(N.count('1'))

Solution (Python):
n = list(input())
print(n.count("1"))

Solution (Python):
S = input()
s1 = int(S[0])
s2 = int(S[1])
s3 = int(S[2])
print(sum([s1, s2, s3]))

Solution (Python):
s = input()
result = int(s[0]) + int(s[1]) + int(s[2])
print(result)

Solution (Python):
n = list(map(int, input()))
count = 0
for i in n: 
    if i == 1: count += 1
print(count)

Solution (Python):
S = input()
result = 0
if S[0] == str(1):
    result= result + 1
if S[1] == "1":
    result = result + 1
if S[2] == '1':
    result = result + 1
print (result)

Solution (Python):
s = input()
counter = 0
if s[0]=='1':
  counter+=1
if s[1]=='1':
  counter+=1
if s[2]=='1':
  counter+=1
print(counter)

Solution (Python):
s = input()
s1,s2,s3 = (int(i) for i in s)
print(s1+s2+s3)

Solution (Python):
l=list(input())
i=0
for j in l:
    if j=="1":
        i+=1
print(i)

Solution (Python):
print(input().count('1'))

Solution (Python):
char = list(input())
sum = 0
for i in char:
    sum+=int(i)
print(sum)

Solution (Python):
print(input().count("1"))

Solution (Python):
print(list(input()).count("1"))

Solution (Python):
s1,s2,s3=map(int,input())
counter=[s1,s2,s3]
print(counter.count(1))

Solution (Python):
s = input()
ans=0
for i in range(3):
    if s[i] == '1':
        ans += 1
print(ans)

Solution (Python):

print(input().count('1'))

Solution (Python):

s = map(int, list(input()))
r = 0
for i in s:
    r += i
print(r)

Solution (Python):
print(input().count('1'))

Solution (Python):
s_list = map(int, list(input()))
count = 0
for s in s_list:
    if s == 1:
        count += 1
    else:
        continue

print(count)

Solution (Python):
s = input()
sum = 0
for i in range(3):
    if s[i] == "1":
        sum += 1
print(sum)

Solution (Python):
string = input()
count = 0
for ch in string:
    if ch == '1':
        count += 1
print(count)

Solution (Python):
s = str(input())
t = list(s)
for i in range(len(t)):
  t[i] = int(t[i])
  
print(t.count(1))

Solution (Python):
count = 0

nums = input()
for num in nums:
    if(num=='1'):
        count = count+1

print(count)

Solution (Python):
print(input().count("1"))

Solution (Python):
S = input()
count = 0
for i in S:
    if i == "1":
        count += 1
print(count)

Solution (Python):
if __name__ == '__main__':

    s = input()
    target = '1'
    count = 0

    for i in s:
        if i == target:
            count = count + 1

    print(count)

Solution (Python):
print(input().count('1'))

Solution (Python):
s = input().count('1')
print(s)

Solution (Python):
N = input()
count = 0
for i in N:
    if i == '1': count += 1

print(count)

Solution (Python):
print(input().count("1"))

Solution (Python):
print(input().count('1'))

Solution (Python):
S=int(input().count("1"))
print(S)

Solution (Python):
a = input()
b = list(a)
print(b.count('1'))

Solution (Python):
print(input().count('1'))

Solution (Python):
s = str(input())
ss = s.split("1")
print(len(ss)-1)

Solution (Python):
print(input().count('1'))

Solution (Python):
str = input()
print(str.count('1'))

Solution (Python):
s = input()
print(s.count('1'))

Solution (Python):
print(input().count("1"))

Solution (Python):
a,b,c = map(int, list(input()))
print(a+b+c)

Solution (Python):
a = input()
count = 0
if a[0] == "1":
    count = count + 1
if a[1] == "1":
    count = count + 1
if a[2] == "1":
    count = count + 1
print(count)

Solution (Python):
s = raw_input()
cnt = 0

for i in range(0, 3):
	if s[i] == "1": cnt = cnt + 1

print cnt

Solution (Python):
a=list(map(int,list(input())))
print(sum(a))

Solution (Python):
print(input().count('1'))

Solution (Python):
print(input().count('1'))

Solution (Python):
s = input()
cnt = 0
for a in s:
  if a == '1':
    cnt += 1
print(cnt)

Solution (Python):
s = input()
print(s.count('1'))

Solution (Python):
def main():
    s = input()
    count = 0
    for s in s:
        if s == "1":
            count += 1
    return count


if __name__ == '__main__':
    print(main())

Solution (Python):
print(sum([int(i) for i in input()]))

Solution (Python):
s=input()
n=0
for i in range(3):
    if s[i]=='1':
        n+=1
print(n)

Solution (Python):
S = int(input())
cnt = 0
for i in range(3):
    if S % 10 == 1:
        cnt += 1
    S = int(S / 10)
print(cnt)

Solution (Python):
print(input().count("1"))

Solution (Python):


s = input()
count = 0
for i in range(len(s)):
    if s[i] == '1':
        count += 1
print(count)

Solution (Python):
print(input().count("1"))

Solution (Python):
print(input().count("1"))

Solution (Python):
from collections import Counter


def main():
    s = input()
    counter = Counter(s)
    print(counter['1'])


if __name__ == '__main__':
    main()

Solution (Python):
s = list(input())
ans = 0
for i in s:
    if i == "1":
        ans += 1
print(ans)

Solution (Python):
a=input()
print(a.count("1"))

Solution (Python):
nums = [int(i) for i in list(input())]
print(sum(nums))

Solution (Python):
s = input()
t = s.count('1')
print(t)

Solution (Python):
a,b,c=map(int,input())
print(a+b+c)

Solution (Python):
n = input()
print(n.count('1'))

Solution (Python):
n = list(map(int, input()))
print(n.count(1))

Solution (Python):
import math
import sys

def getinputdata():

    
    array_result = []
    
    data = input()

    
    array_result.append(data.split(" "))

    flg = 1

    try:


        while flg:

            data = input()

            array_temp = []

            if(data != ""):
                
                array_result.append(data.split(" "))

                flg = 1

            else:

                flg = 0
    finally:


        return array_result





arr_data = getinputdata()

n = arr_data[0][0]



cnt=0
cnt+= 1 if n[0]=="1" else 0
cnt+= 1 if n[1]=="1" else 0
cnt+= 1 if n[2]=="1" else 0

print(cnt)

Solution (Python):
print(input().count('1'))

Solution (Python):
s = list(map(int, input()))
print(s.count(1))

Solution (Python):
i = int(input())
counter = 0

if i/100 >= 1.0:
    counter += 1
    i -= 100
if i/10 >= 1.0:
    counter += 1
    i -= 10
if i == 1:
    counter += 1

print(counter)

Solution (Python):
s = input()
print(s.count("1"))

Solution (Python):
print(input().count('1'))

Solution (Python):


s = input()
res = 0
for c in s:
    if c == "1":
        res += 1

print(res)

Solution (Python):
print(input().count('1'))

Solution (Python):
print(input().count("1"))

Solution (Python):

print(input().count('1'))

Solution (Python):
from collections import Counter

count = Counter(list(input()))

print(count['1'])

Solution (Python):
print(input().count("1"))

Solution (Python):
print(input().count("1"))

Solution (Python):
x = input()
if x =='000' :
     print(0)
if (x == '001' or x == '010' or x == '100'):
    print(1)
if (x == '011' or x == '110' or x == '101'):
    print(2)
if x == '111' :
    print(3)

Solution (Python):
print(input().count("1"))

Solution (Python):
print(input().count('1'))

Solution (Python):

 
def main():
    input_char_list = list(input())
    count = 0
    for char in input_char_list:
        if char == '1':
            count += 1
    print(count)
 
if __name__ == '__main__':
    main()

Solution (Python):
x = input()
answer = 0 
for i in x:
	answer += int(i)
print(answer)

Solution (Python):
print(sum(map(int, list(input()))))

Solution (Python):
print(input().count("1"))

Solution (Python):
print(input().count('1'))

Solution (Python):
a=input()
print(int(a[0])+int(a[1])+int(a[2]))

Solution (Python):
s = str(input())
count = 0

if s[0] == "1":
    count += 1
if s[1] == "1":
    count += 1
if s[2] == "1":
    count += 1

print(count)

Solution (Python):
print(input().count("1"))

Solution (Python):
s = input()
print(s.count('1'))

Solution (Python):
print(input().count('1'))

Solution (Python):
def main():
    s = input()
    cnt = 0
    for c in s:
        if c == "1":
            cnt += 1
    print(cnt)


if __name__ == "__main__":
    main()

Solution (Python):
import sys

stdin = sys.stdin

ni = lambda: int(ns())
na = lambda: list(map(int, stdin.readline().split()))
ns = lambda: stdin.readline()

s = ns()
ans = 0
if s[0] == '1':
    ans += 1
if s[1] == '1':
    ans += 1
if s[2] == '1':
    ans += 1
print(ans)

Solution (Python):
import sys

stdin = sys.stdin

ni = lambda: int(ns())
na = lambda: list(map(int, stdin.readline().split()))
ns = lambda: stdin.readline()

s = ns()
ans = 0
for i in s:
    if i == '1':
        ans += 1
    else:
        pass
print(ans)

Solution (Python):
s = input()
print(int(s[0])+int(s[1])+int(s[2]))

Solution (Python):
s = list(input())
print(int(s[0])+int(s[1])+int(s[2]))

Solution (Python):
s=input()
cnt=0
for i in range(3):
    if s[i]=="1":
        cnt+=1
print(cnt)

Solution (Python):
a = str(input()).split("1")
print(len(a)-1)

Solution (Python):
num = 0

for x in input():
    if x == '1':
        num += 1

print(num)

Solution (Python):
print list(raw_input()).count('1')

Solution (Python):
print(sum(list(map(int,list(input())))))

Solution (Python):
s=list(input())
print(int(s[0])+int(s[1])+int(s[2]))

Solution (Python):





if __name__ == '__main__':
    marble_count = sum(map(int ,list(str(input()))))
    print(marble_count)

Solution (Python):
s = list(map(int,input()))
print(s.count(1))

Solution (Python):
S = input()
print(S.count("1"))

Solution (Python):
print(len(input().replace('0','')))

Solution (Python):

print(input().count('1'))

Solution (Python):
print(input().count('1'))

Solution (Python):
x = list(input())

cnt = 0
for i in range(3):
	if x[i] == "1":
		cnt += 1
print(cnt)

Solution (Python):
S=input()
cnt=0
for i in S:
  if i=='1':
    cnt+=1
print(cnt)

Solution (Python):
import sys
import math
import collections
import itertools
import array
import inspect


sys.setrecursionlimit(10000)


def chkprint(*args):
    names = {id(v):k for k,v in inspect.currentframe().f_back.f_locals.items()}
    print(', '.join(names.get(id(arg),'???')+' = '+repr(arg) for arg in args))


def to_bin(x):
    return bin(x)[2:]


def dim2input(N):
    li = []
    for _ in range(N):
        li.append(list(map(int, input())))
    return li

""" input template
S = input()
N = int(input())
L = list(map(int, input().split()))
a, b = list(map(int, input().split()))
SL = list(input())
"""



dp = None

def main():
    print(input().count("1"))

main()

Solution (Python):


s = input()
cnt = 0
for n in s:
    if n == "1":
        cnt += 1
print((cnt))

Solution (Python):
print(input().count('1'))

Solution (Python):
g = input()
print(g.count('1'))

Solution (Python):
S = int(input())
count = 0
s1 = int(S / 100)
S %= 100
s2 = int(S / 10)
S %= 10
s3 = S
if s1 == 1: count += 1
if s2 == 1: count += 1
if s3 == 1: count += 1
print(count)

Solution (Python):



S = input()

count = 0
for s in S:
    if s == '1':
        count += 1
print(count)

Solution (Python):
s = input()
 
print(int(s[0])+int(s[1])+int(s[2]))

Solution (Python):
s = input()
c = 0
for i in range(3):
    if s[i] == "1":
        c = c+1
print (c)

Solution (Python):
s=input()
num=0
if (s[0]=="1"):
  num+=1
if (s[1]=="1"):
  num+=1
if (s[2]=="1"):
  num+=1
print(num)

Solution (Python):
x = list(input())
print(x.count("1"))

Solution (Python):
a=input()
print(a.count("1"))

Solution (Python):
A=input()
ans=0
for i in range(3):
  if A[i]=='1':
    ans+=1
print(ans)

Solution (Python):
S = input()
print(S.count('1'))

Solution (Python):
x = input()
print(len([c for c in x if c == "1"]))

Solution (Python):


import sys

s = raw_input().split()[0]

n = 0
for c in s:
    if c == '1':
        n += 1

sys.stdout.write('%d\n' % n)
sys.stdout.flush()

Solution (Python):
a=list(input())
print(a.count("1"))

Solution (Python):
print(input().count("1"))

Solution (Python):
s = input()
ans = 0
for i in range(3):
    if s[i] == "1":
        ans += 1
print(ans)

Solution (Python):
s = int(input())
a=int(s/100)
s-=100*a
b=int(s/10)
s-=10*b

print(a+b+s)

Solution (Python):
s=input()
print(s.count('1'))

Solution (Python):
print(input().count("1"))

Solution (Python):

"""
https://beta.atcoder.jp/contests/abc081/tasks/abc081_a

"""
import sys
from sys import stdin
input = stdin.readline


def main(args):
    s = input().strip()
    print(s.count('1'))


if __name__ == '__main__':
    main(sys.argv[1:])

Solution (Python):
a = list(input())
ans = 0
for i in range(3):
  if a[i] == "1":
    ans += 1
print(ans)

Solution (Python):
a = list(input())
ans = 0
for i in range(3):
  if a[i] == "1":
    ans += 1
print(ans)

Solution (Python):
a = list(map(int, list(input())))
print(sum(a))

Solution (Python):
masu = list(input())
count = 0

for i in range(3):
  if masu[i] == '1':
    count += 1
print(count)

Solution (Python):
s = input()
ss = [i for i in s]
print(ss.count("1"))

Solution (Python):
s=int(input())
if s==0:
    print('0')
elif s==10 or s==1 or s==100:
    print('1')
elif s==111:
    print('3')
else:
    print('2')

Solution (Python):





def main():
    S = input()

    ans = sum(c == "1" for c in S)
    print(ans)

if __name__ == "__main__": main()

Solution (Python):
S = input()
print(sum([1 if c == '1' else 0 for c in S]))

Solution (Python):
s = input()
ans = 0
for i in range(3):
    if s[i] == "1":
        ans += 1
print(ans)

Solution (Python):
print len(filter(lambda c: c=="1", raw_input()))

Solution (Python):
print len(filter(lambda c: c=="1", raw_input()))

Solution (Python):
S = input()
print(S.count("1"))

Solution (Python):
s=input()
c=0
for i in s:
    if i=='1':
        c+=1
print(c)

Solution (Python):
print(sum(map(int, list(input()))))

Solution (Python):
x = input()
y = 0
for i in x:
    if i == "1":
        y += 1
print(y)

Solution (Python):
print(input().count("1"))

Solution (Python):
import numpy as np
import pdb

def main():
    string = np.array(list(raw_input()))
    num1 = len(np.where(string == '1')[0])
    print num1

if __name__ == '__main__':
    main()

Solution (Python):
n=int(input());print(n//100+n//10%10+n%10)

Solution (Python):
S=input()
print(S.count("1"))

Solution (Python):
print(sum(map(int,list(input()))))

Solution (Python):
print({
  '000': 0,
  '001': 1,
  '010': 1,
  '011': 2,
  '100': 1,
  '101': 2,
  '110': 2,
  '111': 3
}[input()])

Solution (Python):
print((lambda s: int(s[0])+int(s[1])+int(s[2]))(input()))

Solution (Python):
s = input()
num = list(map(int, str(s)))
print(num.count(1))

Solution (Python):
print(input().count('1'))

Solution (Python):
s = input()
print(int(s[0]) + int(s[1]) +  int(s[2]))

Solution (Python):
a = input()
ans = 0
for b in a:
    if int(b) == 1:
        ans += 1
print(ans)

Solution (Python):
s1,s2,s3= [int(i) for i in input()]
count = 0

if s1 == 1 :
    count+=1
if s2 == 1 :
    count+=1
if s3 == 1 :
    count+=1
print(count)

Solution (Python):
print(input().count("1"))

Solution (Python):



s1, s2 ,s3 = map(int, raw_input())
s = [s1, s2, s3]

print s.count(1)

Solution (Python):

a = input()

ans = 0
for c in a:
    if c == '1':
        ans += 1

print(ans)

Solution (Python):

print(sum(map(lambda s: s == '1', list(input()))))

Solution (Python):
print(input().count('1'))

Solution (Python):
num = str(input())
count = 0

for number in num:
    if number == '1':
        count += 1

print(count)

Solution (Python):
s = input()
print(s.count('1'))

Solution (Python):
number = int(input())

print(number //100 + number % 10 + number %100 // 10)

Solution (Python):
a = list(input())
print(a.count('1'))

Solution (Python):
n = list(input())
print(n.count("1"))

Solution (Python):
a, b, c = map(int, list(input()))
print(a+b+c)

Solution (Python):
import sys

s = sys.stdin.readline()

ss = s.rstrip()

sss =str(ss)
if ss == '000':
    print(0)
if ss == '001':
    print(1)
if ss == '010':
    print(1)
if ss == '011':
    print(2)
if ss == '100':
    print(1)
if ss == '101':
    print(2)
if ss == '110':
    print(2)
if ss == '111':
    print(3)

Solution (Python):
cells = input()
number = cells.count('1')
print(number)

Solution (Python):
a=list(str(input()))
print(a.count('1'))

Solution (Python):
print(input().count('1'))

Solution (Python):
S = input()
print(S.count("1"))

Solution (Python):
s = input()
cnt = 0
for i in s:
    if i == '1':
        cnt += 1
print(cnt)

Solution (Python):
s = input()
print(sum(list(map(int, list(s)))))

Solution (Python):
print(sum([int(n) for n in input()]))

Solution (Python):
a = input()
answer = 0

if a[0] == '1':
    answer += 1
if a[1] == '1':
    answer += 1
if a[2] == '1':
    answer += 1
print(answer)

Solution (Python):
a=int(input())
b1=a // 100
b2=a % 100
c1=b2 // 10
c2=b2 % 10
print(b1+c1+c2)

Solution (Python):
print(input().count("1"))

Solution (Python):
s = input()


print(s.count('1'))

Solution (Python):
a = list(input())
b = 0
for i in a:
    b += int(i)

print(b)

Solution (Python):
print([i for i in input()].count("1"))

Solution (Python):
s = list(input())
ans = 0
for  c in s:
    if c == '1':
        ans+=1

print(ans)

Solution (Python):
s = input()
 
print(int(s[0])+int(s[1])+int(s[2]))

Solution (Python):
print raw_input().count('1')

Solution (Python):

"""
Created on Wed Dec 20 11:35:39 2017

@author: kotania
"""

s = input()

print(int(s[0])+int(s[1])+int(s[2]))

Solution (Python):
s = input()


print(s.count('1'))

Solution (Python):
print(sum(list(map(int,list(input())))))

Solution (Python):
def main():
    print(input().count('1'))


if __name__ == '__main__':
    main()

Solution (Python):
print(input().count("1"))

Solution (Python):

s = list(map(int, list(input())))
print(sum(s))

Solution (Python):
def main():
    s = input()

    ans = s.count("1")
    print(ans)

if __name__ == '__main__':
    main()

Solution (Python):
def solve():
	s = input()
	ans = 0
	for i, c in enumerate(s):
		if c == "1":
			ans += 1
	print(ans)

solve()

Solution (Python):
print(sum(map(int, input())))

Solution (Python):
count = 0
s = input()
for i in s:
    if i == '1':
        count += 1
print(count)

Solution (Python):
num = int(input())
count = 0
if num >= 100:
    count += 1
if num % 100 >= 10:
    count += 1
if num % 10 == 1:
    count += 1

print(count)

Solution (Python):
stdin = input()
ans = 0
for char in stdin:
    if char == "1":
        ans += 1
print(ans)

Solution (Python):
s=input()
print(int(s[0])+int(s[1])+int(s[2]))

Solution (Python):
s=input()

count=0

for c in s:
        if c == '1':
                count+=1

print(count)

Solution (Python):
s = list(input())
s = list(map(lambda x:int(x),s))
count = len(list(filter(lambda x: x==1, s)))
print(count)

Solution (Python):


n = raw_input()

count = 0
for i in n:
    if i == "1":
        count += 1

print count

Solution (Python):


"""
Created on Thu Dec 14 22:14:39 2017

@author: Kanoh
"""


input_line1 = raw_input()
total=0
counter=0
for i in range(len(input_line1)):
    if(int(input_line1[i])==1):
        counter=counter+1
        
print counter

Solution (Python):
S = input()

def main():
    strlen1 = S.replace('0', '')
    result = len(strlen1)
    print(result)

if __name__ == '__main__':
    main()

Solution (Python):
s = input()
ans = 0
for i in s:
    if i == '1':
        ans += 1

print(ans)

Solution (Python):


s=raw_input()
res=0
for i in xrange(3):
 if s[i]=='1':
  res+=1
print res

Solution (Python):
S = input()
cnt = 0
for i in S:
    if i=='1': cnt=cnt+1
print(str(cnt))

Solution (Python):
s = input()
print(s.count("1"))

Solution (Python):
xs = input()
count = 0
for x in xs:
    if x == '1':
        count += 1
print(count)

Solution (Python):
a = input()
print(a.count("1"))

Solution (Python):
list = list(input())
print(list.count('1'))

Solution (Python):
N = list(input())
a = 0

for x in N:
    if x == '1':
        a += 1

print(a)

Solution (Python):
S = input()
cnt = 0
for i in range(3):
    if S[i] == "1":
        cnt += 1
print(cnt)

Solution (Python):
a = raw_input().strip()
print a.count('1')

Solution (Python):
print(input().count("1"))

Solution (Python):
print(input().count("1"))

Solution (Python):
masu = input()
sum = 0
for n in masu:
    sum = sum + int(n)
print(sum)

Solution (Python):
s=input()
print(s.count('1'))

Solution (Python):
l = list(input())
n=0
for i in l :
  if int(i)==1:
    n += 1
print(n)

Solution (Python):
s1s2s3 = input()
i = 0
for ent in s1s2s3:
  if ent == "1":
    i += 1
print(i)

Solution (Python):
n=len([c for c in input().strip() if c =="1"])
print(n)

Solution (Python):
print(sum(c=='1' for c in input()))

Solution (Python):



s = [int(i) for i in input()]


print(sum(s))

Solution (Python):
print sum(map(int,raw_input()))

Solution (Python):
print(sum(map(int, list(input()))))

Solution (Python):
import math,string,itertools,fractions,heapq,collections,re,array,bisect,sys,random,time,copy,functools

sys.setrecursionlimit(10**7)
inf = 10**20
eps = 1.0 / 10**15
mod = 10**9+7

def LI(): return [int(x) for x in sys.stdin.readline().split()]
def LI_(): return [int(x)-1 for x in sys.stdin.readline().split()]
def LF(): return [float(x) for x in sys.stdin.readline().split()]
def LS(): return sys.stdin.readline().split()
def I(): return int(sys.stdin.readline())
def F(): return float(sys.stdin.readline())
def S(): return input()
def pf(s): return print(s, flush=True)
def M(n): return ModInt(n)
def MI(): return M(I())


def main():
    return collections.Counter(S())['1']



print(main())

Solution (Python):
F = raw_input()

print (len(F) - len(F.replace("1", "")))

Solution (Python):
snuke=input()
num=0
for i in snuke:
  if i=='1':
    num += 1
print(str(num))

Solution (Python):
s = raw_input()

ct = 0

for i in s:
    if i == '1':
        ct += 1

print ct

Solution (Python):

from collections import Counter
s = list(input())
a = Counter(s)
print(a['1'])

Solution (Python):
s_input=input()
s = list(s_input)

print(int(s[0])+int(s[1])+int(s[2]))

Solution (Python):
s=input()
print(s.count('1'))

Solution (Python):
num = list(input())
print(num.count('1'))

Solution (Python):
S = bin(int(input(),2)).count("1")
print(S)

Solution (Python):
import sys
from collections import defaultdict, Counter
from itertools import product, groupby, count, permutations, combinations
from math import pi, sqrt, ceil, floor
from collections import deque
from bisect import bisect, bisect_left, bisect_right
from string import ascii_lowercase
from functools import lru_cache, reduce
from operator import xor
INF = float("inf")
sys.setrecursionlimit(10**7)


dy = [0, -1, 0, 1]
dx = [1, 0, -1, 0]


def inside(y: int, x: int, H: int, W: int) -> bool: return 0 <= y < H and 0 <= x < W


def main():
    s = input()
    print(s.count("1"))


if __name__ == '__main__':
    main()

Solution (Python):
inp = input()
inps = list(inp)
count = 0


for i in range(0,3):
	if inps[i] == "1":
		count += 1

print(count)

Solution (Python):
a,b,c=list(input())
cnt=0
if a=='1':
    cnt+=1
if b=='1':
    cnt+=1
if c=='1':
    cnt+=1
print(cnt)

Solution (Python):
s = input()
ans = 0
for i in range(len(s)):
  if s[i]=='1':
    ans += 1

print(ans)

Solution (Python):
print(input().count('1'))

Solution (Python):
x = input()
ans= 0
for i in x:
    if i == '1':
        ans += 1
print(ans)

Solution (Python):
s = input()

if s.count("1") == 0:
	print(0)
	
if s.count("1") == 1:
	print(1)
	
if s.count("1") == 2:
	print(2)

if s.count("1") == 3:
	print(3)

Solution (Python):
s = input()
print(s.count('1'))

Solution (Python):
print(input().count('1'))

Solution (Python):
print(input().count('1'))

Solution (Python):

s = input()
count=0
for c in s:
    if c=='1':
        count+=1
print(count)

Solution (Python):
print(sum(map(int,list(input()))))

Solution (Python):
print(input().count('1'))

Solution (Python):
S = str(input())

count = 0
for s in S:
	if s == "1":
		count += 1
print(count)

Solution (Python):
A=input()
print(A.count('1'))

Solution (Python):
lis = list(input())
count = 0
for item in lis:
    if item == "1":
        count += 1
print (count)

Solution (Python):
s = input()

res = s.count("1")

print(res)

Solution (Python):



a,b,c = map(int,list(input()))
print(a+b+c)

Solution (Python):
print(sum([int(x) for x in input()]))

Solution (Python):
a= input()
ans = 0
if (a[0] == '1'):
    ans = ans+1
if (a[1] == '1'):
    ans = ans+1
if (a[2] == '1'):
    ans = ans+1
print(ans)

Solution (Python):
ans=0
S=input()
for s in S:
    if s=='1':
        ans+=1
print(ans)

Solution (Python):
S = input()
print(S.count("1"))

Solution (Python):
ss=list(str(input()))
r=0
for i in ss:
    r+=int(i)
print(r)

Solution (Python):
S = input()

ans = 0
for i in S:
	if i == "1":
		ans += 1

print(ans)

Solution (Python):
t=list(raw_input())
count=0
for i in t:
    if i == "1":
        count+=1
print count

Solution (Python):
s = input()
print(s.count("1"))

Solution (Python):
s=input()
print(s.count('1'))

Solution (Python):
print(list(map(int, list(input()))).count(1))

Solution (Python):
h1=input()

if h1=='111':
	print(3)
elif h1=='000':
	print(0)
elif h1=='100' or h1=='010' or h1=='001':
	print(1)
else:
	print(2)

Solution (Python):
a = input()
cnt = 0
for i in a:
    if i == "1":
        cnt += 1
print(cnt)

Solution (Python):


N=int(input())
cnt=0

for i in range(3):
    if N%10==1:
        cnt+=1
    N=int(N/10)
print(cnt)

Solution (Python):
i = input(); 
total = 0;
j = 0;
for j in range(0,3): 
  if i[j] == "1":
    total += 1
print(total)

Solution (Python):
s = input()
if s == "001" or s == "010" or s == "100":
    print(1)
elif s == "110" or s == "101" or s == "011":
    print(2)
elif s == "111":
    print(3)
else:
    print(0)

Solution (Python):
num = input()
num_list = []
for i in range(0,3):
    if int(num[i]) == 1:
        num_list.append(i)
num_len = len(num_list)
print(num_len)

Solution (Python):
import numpy
S = input()
print(numpy.array([i=='1' for i in S]).sum())

Solution (Python):
print raw_input().count("1")

Solution (Python):


masu = input()
count = 0
for be in masu:
    be_ = int(be)
    if be_==1:
        count+=1

print(count)

Solution (Python):
a = input().strip()
print(int(a[0])+int(a[1])+int(a[2]))

Solution (Python):
n = int(input())
l = [int(x) for x in list(str(n))]
ans = sum(l)
print (ans)

Solution (Python):
n = input()
print(n.count("1"))

Solution (Python):
I=input()
I2=map(int, I)
X=sum(I2)
print(X)

Solution (Python):
R=input()
count=0

for _ in R:
    if _ =='1':
        count=count+1
print(count)

Solution (Python):


N = input()
N_list = list(N)
N_count = N_list.count("1")

if N_count == 0:
	print("0")
elif N_count == 1:
	print("1")
elif N_count == 2:
	print("2")
elif N_count == 3:
	print("3")

Solution (Python):
a = raw_input()
count = 0
for aa in a:
	if aa == '1':
		count += 1
print count

Solution (Python):


a = int(input())

num = map(int,str(a))
x = 0
for i in num:
    x = x + i

print(x)

Solution (Python):
a = input()
if a == "000":
  print("0")
elif a == "001" or a == "010" or a == "100":
  print("1")
elif a == "111":
  print("3")
else:
  print("2")

Solution (Python):
s = map(int, list(input()))
print(sum(s))

Solution (Python):
tmp = input()

count =0
for i in range(len(tmp)):
    if tmp[i] == "1":
        count +=1
print(count)

Solution (Python):
print(sum([int(x) for x in input()]))

Solution (Python):
print(input().count("1"))

Solution (Python):
a = input()
print(a.count('1'))

Solution (Python):
tables = input()
print(tables.count('1'))

Solution (Python):
import sys

DBG_FLAG = 0

def p_dbg(str):
    if(DBG_FLAG == 1):
        sys.stdout.flush()
        print str


array = map(int,list(raw_input()))

print array[0] + array[1] + array[2]

Solution (Python):
print(sum([int(i) for i in input()]))

Solution (Python):


h=int(input())
a = (h//4)%2 + (h//2)%2 + h%2
print(a)

Solution (Python):
N = list(input())
print(N.count('1'))

Solution (Python):



S = input()
S_list = list(S)
s = 0

for i in range(len(S_list)):
    S_list[i] = int(S_list[i])
for j in range(len(S_list)):
    s += S_list[j]
print(s)

Solution (Python):


if __name__ == '__main__':
    N = input()
    cnt = 0

    for i in N:
        if i == "1":
           cnt += 1

    print(cnt)

Solution (Python):


s = str(input())
cnt = 0

for a in range(3):
	if s[a] == '1': cnt +=1

print(cnt)

Solution (Python):
instr = input()
out = 0 
if instr[0] == "1":
    out += 1
if instr[1] == "1":
    out += 1
if instr[2] == "1":
    out += 1
print(out)

Solution (Python):
S = str(input())
cnt=0
for s in S:
    if (s == '1'):
        cnt += 1

print(cnt)