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-----
101

-----Sample Output-----
2

 - A marble will be placed on Square 1 and 3.

Difficulty: introductory

Starter code:

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

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


# -*- coding: utf-8 -*-
# 整数の入力
s = input()
number = "1"

count = s.count(number)
print(count)

print(input().count("1"))

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

import bisect,collections,copy,heapq,itertools,math,string
import sys
def I():
    #1 line 1 int
     return int(sys.stdin.readline().rstrip())
def LI():
    #1 line n int
     return list(map(int,sys.stdin.readline().rstrip().split()))
def S():
    #1 line 1 string
     return sys.stdin.readline().rstrip()
def LS():
    #1 line n strings
     return list(sys.stdin.readline().rstrip().split())

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

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

s = list(input())
count = 0
for i in range(0, len(s)):
    if s[i] == "1":
        count += 1

print(count)

import bisect,collections,copy,heapq,itertools,math,string
import sys
def I():
    # 1 line 1 int
    return int(sys.stdin.readline().rstrip())
def LI():
    # 1 line n ints
    return list(map(int,sys.stdin.readline().rstrip().split()))
def S():
    # 1 line 1 string
    return sys.stdin.readline().rstrip()
def LS():
    # 1 line n strings
    return list(sys.stdin.readline().rstrip().split())

x = S()

count = 0
for s in x:
    if s == "1":
        count += 1

print(count)

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

s = list(map(int, input()))
count = 0
for i in range(len(s)):
  if s[i] == 1:
    count +=1
print(count)

a = input()
count = 0
for i in a:
    if i == '1':
        count += 1
    else:
        pass
print(count)


print(sum([int(ss) for ss in input()]))

s1,s2,s3 = list(map(str, input()))
counter = 0
if s1 == "1":
    counter += 1
if s2 == "1":
    counter += 1
if s3 == "1":
    counter += 1
print(counter)


m = 0
for s in list(input()):
    if int(s) == 1:
        m += 1
print(m)


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

S = input()
count = 0

if S[0] == '1':
    count += 1
if S[1] == '1':
    count += 1
if S[2] == '1':
    count += 1
    
print(count)

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

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

s = list(input())

ans = 0

for i in range(len(s)):
  if s[i] == '1':
    ans += 1
else:
  print(ans)

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

st_list = list(input())
nu_list = [int(v) for v in st_list]
count = 0
for i in range(len(nu_list)):
  if nu_list[i] == 1:
    count += 1
print(count)

n = input()
result = sum(list(map(int,str(n))))
print(result)

s=input()
count=0

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

print(count) 

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

# coding: utf-8
# Your code here!

cnt_1 = 0

list_S = input()

for i in list_S : 
    if i == "1" : 
        cnt_1 += 1
        
print(cnt_1)

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

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

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

s = input()
s_c = s.count("1")
print(s_c)

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

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

a=str(input())
count=0
for i in range(3):
    if a[i-1]=="1":
        count+=1
print(count)

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

print(ans)


s = input()
ans = 0
for i in s:
    ans += int(i)
print(ans)

#!/usr/bin/env python3
import sys
sys.setrecursionlimit(10**6)

s = list(str(input()))

ans = [1 if i == "1" else 0 for i in s]

print((sum(ans)))


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

s = input()

print(s.count("1"))

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

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


b = input()
a = str(b)
i = 0
if a[0] == '1':
    i += 1
if a[1] == '1':
    i += 1
if a[2] == '1':
    i += 1
print(i)


print(input().count("1"))

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

print(input().count("1"))

s = list(map(int,input()))
count = 0

for n in s:
    if n == 1:
        count+=1
        
print(count)

print(input().count("1"))

s = input()
a, b, c = int(s[0]), int(s[1]), int(s[2])
count = 0
if a == 1:
  count+=1
if b == 1:
  count+=1
if c == 1:
  count+=1
print(count)

#第2問　ABC081A
number = list(map(int,input()))
a = 0
for i in number:
    if i == 1:
        a = a+1
print(a)

s = input()

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

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

n = input()
print(n.count("1"))

s = str(input())
print(s.count('1'))

a=input()
count=0

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

print(count)


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

print(input().count("1"))

getints = lambda: list(map(int, input().split()))
s = input()
ans = 0
for c in s:
    if c == '1':
        ans += 1
print(ans)


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

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

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

a = int(input())

count = 0

# print(int(a/100))
if int(a / 100) == 1:
    count += 1

#print(int(a/10 % 10))
if int(a / 10 % 10) == 1:
    count += 1

#print(int(a % 100 % 10))
if int(a % 100 % 10) == 1:
    count += 1

print(count)


li = list(input())
c = 0
for i in li:
    if i == '1':
        c += 1

print(c)

s = str(input())
ans = int(s[0])+int(s[1])+int(s[2])
print(ans)

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

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


print(input().count("1"))

s=list(input())
res=0
for i in s:
    if (i=='1'):
        res+=1
print(res)

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

A = input()

ans=int(0)

if A[0] == "1":
    ans = ans + 1

if A[1] == "1":
    ans = ans + 1

if A[2] == "1":
    ans = ans + 1

print(ans)

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

s = list(input())
cnt = 0
for item in s:
  if (int(item) == 1):
    cnt = cnt + 1
print(cnt)

i = str(input())
s1, s2, s3 = int(i[0]), int(i[1]), int(i[2])
print(int(s1+s2+s3))

D = input()

A="1"
B="11"
C="101"
F="111"

if F == D:
    print((3))
    
elif B in D:
    print((2))

elif C == D:
    print((2))

elif A in D:
    print((1))

else:
    print((0))


s = input()
cnt = 0

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

print(cnt)


s1,s2,s3 = map(int, input())

number_list = [s1,s2,s3]

counter = 0

for i in range(len(number_list)):
    if number_list[i] == 1:
        counter += 1
print(counter)

s = input()

print(s.count("1"))

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

s = list(input())
print(s.count("1"))



# Press the green button in the gutter to run the script.
def __starting_point():
    s = input()

    count = 0
    for n in range(3):
        if s[n] == '1':
            count = count + 1

    print(count)

__starting_point()

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

a = input()

b = a.count('1')
print(b)

area = input()
print(area.count("1"))

print(input().count("1"))

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


main()

s = list(input())

print(s.count('1'))

def iroha():
    num = input()
    count = 0

    for i in num:
        if i == '1':
            count+=1
    
    print(count)


def __starting_point():
    iroha()


__starting_point()

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


s = input()
ans = 0

for i in s:
    if i == "1":
        ans += 1

print(ans)

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


s = input()
ans = 0
for i in s:
    ans += int(i)
print(ans)

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

# 文字列の入力
s = input()

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

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

def solve(s):
    count = 0
    if s[0] == '1':
        count += 1
    if s[1] == '1':
        count += 1
    if s[2] == '1':
        count += 1
    print(count)


def __starting_point():
    solve(input())

__starting_point()

a = input()
print(a.count("1"))

#81
data=list(input())
c=0
for i in range(0,len(data)):
    if data[i]=='1':
        c=c+1
print(c)

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

print(input().count("1"))

s = input()

print(s.count("1"))

s = input()
 
cnt = sum([int(c) for c in s])
print(cnt)