Problem:
 Score : 200 points    Problem Statement You are given a string s consisting of lowercase English letters. Extract all the characters in the odd-indexed positions and print the string obtained by concatenating them. Here, the leftmost character is assigned the index 1 .      Constraints  Each character in s is a lowercase English letter.  1≤|s|≤10^5         Input The input is given from Standard Input in the following format:  s       Output Print the string obtained by concatenating all the characters in the odd-numbered positions.        Sample Input 1 atcoder      Sample Output 1 acdr  Extract the first character a , the third character c , the fifth character d and the seventh character r to obtain acdr .       Sample Input 2 aaaa      Sample Output 2 aa       Sample Input 3 z      Sample Output 3 z       Sample Input 4 fukuokayamaguchi      Sample Output 4 fkoaaauh

Solution (Python):



import unittest
from io import StringIO
import sys


def input():
    return sys.stdin.readline().rstrip()


def resolve():
    s = input()

    ans = ""
    for i in range(len(s)):
        if (i+1) % 2 == 1:
            ans += s[i]
    print(ans)


class TestClass(unittest.TestCase):
    def assertIO(self, input, output):
        stdout, stdin = sys.stdout, sys.stdin
        sys.stdout, sys.stdin = StringIO(), StringIO(input)
        resolve()
        sys.stdout.seek(0)
        out = sys.stdout.read()[:-1]
        sys.stdout, sys.stdin = stdout, stdin
        self.assertEqual(out, output)

    def test_入力例_1(self):
        input = """atcoder"""
        output = """acdr"""
        self.assertIO(input, output)

    def test_入力例_2(self):
        input = """aaaa"""
        output = """aa"""
        self.assertIO(input, output)

    def test_入力例_3(self):
        input = """z"""
        output = """z"""
        self.assertIO(input, output)

    def test_入力例_4(self):
        input = """fukuokayamaguchi"""
        output = """fkoaaauh"""
        self.assertIO(input, output)


if __name__ == "__main__":
    
    resolve()

Solution (Python):
N=input()
n=[]
r=[]
for i in range(0,len(N)):
    n.append(N[i])
for j in range(0,len(n)):
    if j%2==0:
        r.append(n[j])
s="".join(r)
print(s)

Solution (Python):

s = input()

l = (len(s) + 1) // 2 
for i in range(l):
    print(s[i * 2], end = '')

Solution (Python):
s=list(input())
s=[s[i] for i in range(len(s)) if i %2==0]
print("".join(s))

Solution (Python):
s=input()
t=''
for i,c in enumerate(s):
    if i%2==0:
        t+=c
print(t)

Solution (Python):
s=input()

for i in range(len(s)):
	if i%2==0:
		print(s[i],end='')
print()

Solution (Python):

s = open(0).read()

print(s[::2])

Solution (Python):
"""
author : halo2halo
date : 25,Oct,2019
"""

import sys
readline = sys.stdin.readline
readlines = sys.stdin.readlines
sys.setrecursionlimit(10 ** 7)

S = readline().rstrip()
print(S[::2])

Solution (Python):
s = input()

print(s[::2])

Solution (Python):
print(input()[::2])

Solution (Python):
n = input()
print(n[::2])

Solution (Python):
S = input()

for i in range(0, len(S), 2):
    print(S[i], end="")

Solution (Python):
print(input()[::2])

Solution (Python):
s = input()
print(s[::2])

Solution (Python):
s=input()
print(s[::2])

Solution (Python):
S=input()
n=""
for i in range(len(S)):
  if i%2==0:
    n+=S[i]
print(n)

Solution (Python):
print(input()[0::2])

Solution (Python):
s=list(map(str, input()))
A=[]
i=0
l=len(s)
if l==1:
    l+=1
l=l/2
l=round(l)
for i in range(l):
      A.append(s[2*i])
A=''.join(A)
print(A)

Solution (Python):
s=input()
n=len(s)
l=''
for i in range(0,n,2):
    l+=s[i]
print(l)

Solution (Python):
s=input()
S=list(s)
x=[]
for i in range(int((len(S)+1)/2)):
    x.append(S[2*i])
a=''.join(x)
print(a)

Solution (Python):
s=input()
t=''
for i in range(0,len(s),2):
    t+=s[i]
print(t)

Solution (Python):
s=input()
for i in range(len(s)):
    if i%2==0:
        print(s[i],end="")
print("\n")

Solution (Python):


s = input()
list = range(0, len(s), 2)
s_result = ''
for i in list:
    s_result = s_result + s[i]

print(s_result)

Solution (Python):
s = input()
print(s[::2])

Solution (Python):
print(input()[::2])

Solution (Python):
print(input()[::2])

Solution (Python):
s = input()
print(s[::2])

Solution (Python):
s = input()
for i, r in enumerate(s):
  if i%2==0:
    print(r, end="")

Solution (Python):
s=input()
print(s[::2])

Solution (Python):
s=input()
for i in range(len(s)):
  if i%2==0:
    print(s[i],end="")
print("")

Solution (Python):
print(input()[::2])

Solution (Python):
s = input()

ans = ''
for i in range(len(s)):
    if (i+1) % 2 == 1:
        ans += s[i]

print(ans)

Solution (Python):
s = input().strip()
x = ""
for i in range(0,len(s),2):
    x += s[i]
print(x)

Solution (Python):

S = input()
ans = ''

for i,s in enumerate(S):
    if i%2 == 0:
        ans += s

print(ans)

Solution (Python):

s=list(input())
lens=len(s)
l=(lens+1)//2
ans=[]

for n in range(l):
  ans.append(s[2*n])

print(''.join(ans))

Solution (Python):
s = input()
print(s[::2])

Solution (Python):
s=str(input())
ans=str('')
for i in range(0,len(s),2):
  ans+=s[i]
print(ans)

Solution (Python):
n = input()
for i in range(1+(len(n)-1)//2):
  print(n[2*i], end='')

Solution (Python):
print(input()[::2])

Solution (Python):
s = input()

print(s[::2])

Solution (Python):
s = input()

ans = ''
for i in range(0, len(s), 2):
    ans += s[i]

print(ans)

Solution (Python):
s = list(input())
string = ''
for i in range(len(s)):
    if i%2 == 0:
        string += s[i]
print(string)

Solution (Python):
s = list(input())
string = ''
for i in range(len(s)):
    if i%2 == 0:
        string += s[i]
print(string)

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

Solution (Python):
s=input()
a=[s[2*k] for k in range(0,int((len(s)+1)/2))]
print("".join(a))

Solution (Python):
s = input()
ans = ''
for i in range(len(s)):
    if i % 2 == 0:
        ans += s[i]
print(ans)

Solution (Python):
s=input()
print(s[::2])

Solution (Python):
s=input()
print(s[::2])

Solution (Python):
def slove():
    import sys
    input = sys.stdin.readline
    s = list(str(input().rstrip('\n')))
    print("".join(s[::2]))


if __name__ == '__main__':
    slove()

Solution (Python):
s=input()

for i in range(0,len(s),2):
    print(s[i],end='')


print()

Solution (Python):
print("".join((input()[0::2])))

Solution (Python):
print(input()[::2])

Solution (Python):
print(input()[::2])

Solution (Python):
s = list(input())
o = []
for i, t in enumerate(s):
    if (i + 1) % 2 == 1:
        o.append(t)
print(''.join(o))

Solution (Python):
s = input()
ans = ""

for i in range(len(s)):
    if i % 2 == 0:
        ans += ans.join(s[i])
print(ans)

Solution (Python):
import math
s=input()
li=[]

l=len(s)+1

for i in range(0,math.floor(l/2)):
    li.append(s[2*i])

str=''.join(li)
print(str)

Solution (Python):
s = input()
ans = ""
for i in range(0, len(s), 2):
    ans += s[i]
print(ans)

Solution (Python):
s = list(input())
n = len(s)
s_odd = []

for i in range(0, n, 2):
    s_odd.append(s[i])

print(''.join(s_odd))

Solution (Python):
s = input()

for i in range(0, len(s), 2):
    print(s[i], end="")

Solution (Python):
s = input()
res = []
for i in range(len(s)):
    if i % 2 == 0:
        res.append(s[i])
print("".join(res))

Solution (Python):
print(input()[::2])

Solution (Python):
import sys

if sys.platform =='ios':
    sys.stdin=open('input_file.txt')
    
print(input()[::2])

Solution (Python):
s=str(input())
print(s[::2])

Solution (Python):
print(input()[::2])

Solution (Python):
s=input()
a=""
for i in range(0,len(s),2):
    a+=s[i]
print(a)

Solution (Python):
a = input()

print(a[0::2])

Solution (Python):
s = input()
ans = ""
for i in range(0, len(s), 2):
    ans += s[i]
print(ans)

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

Solution (Python):
s = input()
print(s[::2])

Solution (Python):
print(input()[::2])

Solution (Python):
s=input()
l=[]
for i in range(len(s)):
  if i%2==0:
    l.append(s[i])
print("".join(l))

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

Solution (Python):
s = list(input())
a = list(s[::2])
print(''.join(a))

Solution (Python):
print(input()[::2])

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

for i in range(0,len(s),2):
    print(s[i],end="")
print()

Solution (Python):
print(input()[::2])

Solution (Python):
s = input()
n = len(s)
print("".join([s[x] for x in range(0, n, 2)]))

Solution (Python):
s = list(input())
print("".join([i for i in s[0:len(s):2]]))

Solution (Python):

s = input()
print(s[::2])

Solution (Python):
s=input()
print(''.join(s[::2]))

Solution (Python):
st = input()
ans = [s for ind, s in enumerate(st) if ind % 2 == 0]
ans = ''.join(ans)
print(ans)

Solution (Python):
s=input()
ans=""
for i in range(len(s)):
  if i % 2 == 0:
    ans+=s[i]
print(ans)

Solution (Python):
import sys
input = sys.stdin.readline

s = list(input().strip())
t = 0
li = []

for i in s:
    if t % 2 == 0:
        li.append(i)
    t += 1

li = ''.join(li)

print(li)

Solution (Python):
print(input()[::2])

Solution (Python):
s = input()
ans = ""
for i in range(len(s)):
    if i % 2 == 0:
        ans += s[i]
print(ans)

Solution (Python):
import sys
input = sys.stdin.readline


def main():
    s = input()[:-1]
    ans = ''
    for i in range(len(s)):
        if i%2==0:
            ans += s[i:i+1]
    print(ans)

if __name__ == '__main__':
    main()

Solution (Python):
s = input()
ans = ""
for i in range(len(s)):
  if i%2 == 0:
    ans += s[i]
print(ans)

Solution (Python):
s = input()
for c in range(0, len(s), 2):
    print (s[c],end="")

Solution (Python):
s = input()
ans = ''

for i in range(len(s)):
    if i % 2 == 0:
        ans += s[i]

print(ans)

Solution (Python):
print(input()[::2])

Solution (Python):
s=list(input())
ans=[]
for i in range(len(s)//2+len(s)%2):
    ans+=s[2*i]
print(''.join(ans))

Solution (Python):
s = list(input())
n = 0
ans = []
for i in s:
    if n % 2 == 0:
        ans.append(i)
    n += 1
answer = ''.join(ans)
print(answer)

Solution (Python):
s = input()

for i in range(len(s)):
    if i % 2 == 0:
        print(s[i], end="")

Solution (Python):
s = list(input())
for i in range(0, len(s), 2):
    print(s[i], end="")

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

Solution (Python):
s = input()
oddstring = ''

for i in range(len(s)):
    if i%2 == 0 or i == 0:
        oddstring = oddstring + s[i]

print(oddstring)

Solution (Python):
print(input()[::2])

Solution (Python):
s = list(input())
s1 = ''.join(s[0::2])
print(s1)

Solution (Python):
s = input()
t = len(s)/2 - len(s)//2
u = ''
if t==0:
  for i in range(len(s)//2):
    u += s[2*i]
else:
  for i in range(len(s)//2+1):
    u += s[2*i]
print(u)

Solution (Python):
s = input()
print(s[::2])

Solution (Python):
s = input()
print(s[::2])

Solution (Python):
s = input().rstrip()
print(s[::2])

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

Solution (Python):
s=input()
print(s[::2])

Solution (Python):
s = input()
a =[]
for i in range(len(s)):
  if (i+1)%2 !=0:
    a.append(s[i])
print(''.join(a))

Solution (Python):
import sys
import math
from fractions import gcd





def lcm(a, b):
    return a * b // gcd(a, b)

def combination_count(n, r):
    return math.factorial(n) // (math.factorial(n - r) * math.factorial(r))

def permutations_count(n, r):
    return math.factorial(n) // math.factorial(n - r)

big_prime = 1000000007

"""


 = sys.stdin.readline().rstrip()
 = list(sys.stdin.readline().rstrip())


 = int(sys.stdin.readline())
 = map(int, sys.stdin.readline().split())
 = list(map(int, sys.stdin.readline().split()))
 = [list(map(int,list(sys.stdin.readline().split()))) for i in range(N)]
"""


S = sys.stdin.readline().rstrip()

A = S[::2]
print(A)

Solution (Python):
s = input()

ans = ''

for i in range(len(s)):
    if i % 2 == 0:
        ans += s[i]

print(ans)

Solution (Python):
print(input()[::2])

Solution (Python):
print(input()[::2])

Solution (Python):
print(input()[0::2])

Solution (Python):
print(input()[::2])

Solution (Python):

s = input()

even_s = ''
count = -1
for i in s:
    count += 1
    if count % 2 == 0:
        even_s = even_s + i

print(even_s)

Solution (Python):
s = input()
ans = ""
for i in range(len(s)):
    if i%2==0:
        ans += s[i]
print(ans)

Solution (Python):
def resolve():
    s = input()
    print("".join(s[::2]))


if __name__ == "__main__":
    resolve()

Solution (Python):
s=input()
print(s[::2])

Solution (Python):
s = input()
ans = ""
for i in range(len(s)):
    if i % 2 == 0:
        ans += s[i]
print(ans)

Solution (Python):
print(input()[::2])

Solution (Python):
print(input()[0::2])

Solution (Python):

s = input()
array = list(s)

ans = ''
for i in range(len(s)):
    if i % 2 == 0:
        ans = ans + array[i]

print(ans)

Solution (Python):
s = input()

print(''.join(s[::2]))

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

ans=''
for i in range(len(s)):
    if i%2==0:
        ans+=s[i]
print(ans)

Solution (Python):
s = input()
ans = ""
for i in range(len(s)//2+len(s)%2):
    ans += s[2*i]
print(ans)

Solution (Python):
s = str(input())
print(s[0::2])

Solution (Python):
s = input()

print(s[::2])

Solution (Python):
s = input()
print(s[::2])

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

S_odd = list([S[i] for i in range(len(S)) if i%2==0])

print(*S_odd,sep='')

Solution (Python):
print(input()[::2])

Solution (Python):
string = input()

cnt = 1
ans = ''

for char in string:
    if (cnt % 2) == 1:
        ans += char
    cnt += 1
    
print(ans)

Solution (Python):
print(input()[::2])

Solution (Python):
s = input()
res = ""
for i in range(len(s)):
    if i % 2 == 0:
        res += s[i]
print(res)

Solution (Python):
print(input()[::2])

Solution (Python):
print(input()[::2])

Solution (Python):
s=input()
print(s[::2])

Solution (Python):
s = input()
ans = ""
for i in range(0, len(s), 2):
    ans += s[i]
print(ans)

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

n=len(s)
ans=[]
for i in range(0,n,2):
    ans.append(s[i])
print(''.join(ans))

Solution (Python):
s = input()
print(s[::2])

Solution (Python):
s = input()
print(s[::2])

Solution (Python):
s = input()
print(s[::2])

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

Solution (Python):
s = input()

print(s[::2])

Solution (Python):
import sys
input = sys.stdin.readline

def main():
    s = input().strip()

    for i in range(0, len(s), 2):
        print(s[i], end="")
    print()


if __name__ == "__main__":
    main()

Solution (Python):
print(''.join([c for i,c in enumerate(input().strip()) if i%2 == 0]))

Solution (Python):

s = input()
print(s[::2])

Solution (Python):
s=input()
t=s[0]
if len(s)/2==0:
  n=int(len(s)/2)-1
else:
  n=int((len(s)-1)/2)
for i in range(n):
  t+=s[2*(i+1)]
print(t)

Solution (Python):
s=input()
print(s[::2])

Solution (Python):
s = input()
print(s[::2])

Solution (Python):
print(input()[::2])

Solution (Python):
print(input()[0::2])

Solution (Python):
S = input()
print(*S[::2], sep='')

Solution (Python):
s=input()
print(s[::2])

Solution (Python):
import sys
import copy
import  math
import bisect
from collections import *
from operator import itemgetter
"""
from fractions import gcd
def lcm(x, y):
    return (x * y) // gcd(x, y)
"""
stdin = sys.stdin
ni = lambda: int(ns())
na = lambda: list(map(int, stdin.readline().split()))
ns = lambda: stdin.readline()

s = input()
print(s[0::2])

Solution (Python):
word = input()

ans = ""

for num, i in enumerate(word):
  if num % 2 == 0:
    ans += i
print(ans)

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

ans = [a for a in s[::2]]
print(''.join(ans))

Solution (Python):

import sys
input = sys.stdin.readline
sys.setrecursionlimit(10**6)

s = input()
ans = ''

for i in range(0, len(s), 2):
    ans += s[i]
print(ans)

Solution (Python):

import sys
input = sys.stdin.readline
sys.setrecursionlimit(10**6)

s = input()

for i in range(0, len(s), 2):
    print(s[i], end='')

Solution (Python):
L = input()
print(L[::2])

Solution (Python):
s = input()

print(s[0::2])

Solution (Python):
print(input()[::2])

Solution (Python):
print(input()[::2])

Solution (Python):
s = input()

ans = ""
for i in range(0, len(s), 2):
    ans += s[i]

print(ans)

Solution (Python):
n = input()
ln=len(n)
ans=[]
for i in range(ln):
	if i % 2 == 0:
		ans.append(n[i])
	else:
		continue
print(''.join(ans))

Solution (Python):
s=input()
print(s[0:len(s):2])

Solution (Python):
s = input()
S = ""
if len(s)%2 != 0:
  for i in range(len(s)//2+1):
    S += s[i*2]
else:
  for i in range(len(s)//2):
    S += s[i*2]
print(S)

Solution (Python):
print(input()[::2])

Solution (Python):
print(input()[0::2])

Solution (Python):
s=input()
n=""
for i in range(0,len(s),2):
    n=n+s[i]
print(n)

Solution (Python):
print(input()[0::2])

Solution (Python):
s = input()

print(s[::2])

Solution (Python):
def test():
    s = list(input())
    print("".join([x for n,x in enumerate(s) if n%2 == 0]))


if __name__ == "__main__":
    test()

Solution (Python):
s = input()
ans = ""
for i in range(0, len(s), 2):
    ans += s[i]
print(ans)

Solution (Python):
s=input()
print(s[::2])

Solution (Python):
s=input()


print(s[::2])

Solution (Python):
print(input()[::2])

Solution (Python):
S = input()
s = ""
for i in range(len(S)):
  if i%2==0:
    s += S[i]
print(s)

Solution (Python):
s = input()
print(s[::2])

Solution (Python):
s = input()
print(s[::2])

Solution (Python):
s = list(input())
ss = []
for i in range(len(s)):
         if i % 2 == 0:
                  ss.append(s[i])
else:
         answer=''.join(ss)
         print(answer)

Solution (Python):
s = input()
for i in range(len(s)):
    if i % 2 == 0:
        print(s[i],end="")

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

Solution (Python):


s = input()

i = 0
odd = []

for c in list(s):
    if i % 2 == 0:
        odd.append(c)
    i += 1

print("".join(odd))

Solution (Python):
print(input()[::2])

Solution (Python):
s=input()
N=len(s)
ans=str()

for i in range(0, N, 2):
    ans+=s[i]
print(ans)

Solution (Python):
s=input()
N=len(s)
ans=''

for i in range(0, N, 2):
    ans+=s[i]
print(ans)

Solution (Python):
def main():
    s = input()
    return s[::2]



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

Solution (Python):
a = input()
l = len(a)
aa=[]

for i in range(l):
  if i%2 == 0:
    aa.append(a[i])

print("".join(aa))

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

box = []

for x in range(0,len(S),2):
     box.append(S[x])
    
print(''.join(box))

Solution (Python):
S = input()
N = len(S)
ans = ''
for n in range(0, N, 2):
    ans += S[n]
print(ans)

Solution (Python):
print(''.join(list(input())[::2]))

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

Solution (Python):
print(input()[::2])

Solution (Python):
print(input()[::2])

Solution (Python):
s=input()
print(s[::2])

Solution (Python):
s = input()
r = s[0::2]
print(r)

Solution (Python):
S = input()
ans = ""
for i in range(1,len(S)+1):
  if i % 2 == 1:
    ans += S[i-1]

print(ans)

Solution (Python):
import math
s = input()
ans = ""
for i in range(math.ceil(len(s)/2)):
    ans += s[2*i]
print(ans)

Solution (Python):


def main():

    print(''.join([ans for ans in input()[::2]]))
    
if __name__== "__main__":
    main()

Solution (Python):
s=input()
print(s[::2])

Solution (Python):
s=input()
print(s[::2])

Solution (Python):
s = input()
a = ""
for i in range((len(s)+1)//2):
  a = a+ str(s[2*i])
print(a)

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

Solution (Python):
s=input()

ans=[tmp for i,tmp in enumerate(s) if (i+1)%2==1]
print(*ans,sep='')

Solution (Python):
print(input()[::2])

Solution (Python):
print(input()[::2])

Solution (Python):
s = input()
for i in range(len(s)):
    if (i + 1) % 2 == 1:
        print(s[i], end='')
print()

Solution (Python):


def main(s):
    A = []
    for i in range(0,len(s),2):
        A.append(s[i])
    print("".join(A))

if __name__ == '__main__':
    s = list(input())
    main(s)

Solution (Python):
s=input()
print(s[::2])

Solution (Python):
s = input()
odd_s = ''

for i in range(len(s)):
  if i%2 == 0:
    odd_s = odd_s + s[i]
print(odd_s)

Solution (Python):
S = input()

ans = []
for i in range(len(S)):
    if (i + 1) % 2 != 0:
        ans.append(S[i])

print("".join(ans))

Solution (Python):
print("".join([ch for (i, ch) in enumerate(input()) if i % 2 == 0]))

Solution (Python):



s = input()


print(s[::2])

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

Solution (Python):
s = input()
print(s[::2])

Solution (Python):
x = [i for i in input()]
n = []
for j in range(0,len(x),2):
  n.append(x[j])
print("".join(n))

Solution (Python):
s = input()
length = len(s)

for i in range(0,length,2):
  print(s[i],end="")

Solution (Python):
s=input()
for i in range(len(s)):
    if i%2==0:
        print(s[i],end="")

print("")

Solution (Python):
s = input()

a = []

for i in range(len(s)):
	if i%2 == 0:
		a.append(s[i])

a = ''.join(a)

print(a)

Solution (Python):
print(input()[::2])

Solution (Python):
s = input()
print(s[::2])

Solution (Python):
s = input()
print(s[::2])

Solution (Python):
print(input()[::2])

Solution (Python):

s = input()


res = [s[i] for i in range(len(s)) if (i + 1) % 2 != 0]


print(''.join(res))

Solution (Python):
s = input()
r = list()
for i,ss in zip(range(len(s)),s):
    if (i % 2 ==0):
            r.append(ss)
print("".join(r))

Solution (Python):
print(input()[0::2])

Solution (Python):
s = input()

ans = ''

for i in range(0, len(s), 2):
    ans += s[i]
print(ans)

Solution (Python):
s = input()
print(s[::2])

Solution (Python):
s = input()
print(s[::2])

Solution (Python):
print(input()[::2])

Solution (Python):
a = input()
b = len(a)

num = []

for x in range(0,b,2):
    num.append(x)
    
for i in num:
    print(a[i], end='')

Solution (Python):
s = input()
l = []

for i in range(len(s)):
  if i % 2 == 0:
    l.append(s[i])
    
print(''.join(l))

Solution (Python):
s = input()
s_list = []
for i in range(len(s)):
    if i % 2 == 0:
        s_list.append(s[i])
ss = ''.join(s_list)
print(ss)

Solution (Python):
s = list(input())
ss = s[::2]
print(''.join(ss))

Solution (Python):
s=input()
answer=""
for i in range(0,len(s),2):
    answer+=s[i]
    
print(answer)

Solution (Python):
print(input()[::2])

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

result_lst = []
for i in range(len(s)):
    if i%2 == 0:
        result_lst.append(s[i])

print(''.join(result_lst))

Solution (Python):
print(input()[::2])

Solution (Python):
s = input()
for i in range(len(s)):
  if i%2 == 0:
    print(s[i], end = '')

Solution (Python):
s = input()
t = ''
i = 0
while i <= len(s)-1:
  t += s[i]
  i += 2
print(t)

Solution (Python):
S = input()

ans = ''
for i in range(len(S)):
    if (i+1)%2 == 1:
        ans += S[i]
print(ans)

Solution (Python):
s = input()
print(s[::2])

Solution (Python):
s = input()
print("".join(s[::2]))

Solution (Python):
a = [i for i in input() ]
b = []
for g in range(len(a)):
    if g%2 ==0:
        b.append(a[g])
print(''.join(b))

Solution (Python):
s=input()
print(s[::2])

Solution (Python):
s = list(input())
join_s = []
for i in range(len(s)):
  if i % 2 == 0:
    join_s.append(s[i])
print(''.join(join_s))

Solution (Python):
a = input()
for i in range(len(a)):
  if i % 2 == 0:
    print(a[i],end='')

Solution (Python):
s = input()

tstr = ''
for i in range(len(s)):
    num = i+1
    if num % 2 == 1:
        tstr += s[i]
print(tstr)

Solution (Python):
s = input()
print(s[::2])

Solution (Python):
s = list(input())
print(''.join(s[0::2]))

Solution (Python):
print (input()[::2])

Solution (Python):
S = input()
print(S[0::2])

Solution (Python):
Strings = input()
result = ''
for i in range(0,len(Strings),2):
    result += Strings[i]
print(result)

Solution (Python):
s = input()
s = s[::2]
print(s)

Solution (Python):
s = input()
print(s[::2])

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

Solution (Python):
s = input()
for i in range(1,len(s)+1):
    if i % 2 == 1:
        print(s[i-1],end="")

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

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

n=len(sl)
li=[]
for i in range(1,n+1) :
  if i % 2 != 0 :
    li.append(sl[i-1])
print(*li,sep="")

Solution (Python):
if __name__ == '__main__':
    s = input()
    print(s[0::2])

Solution (Python):
s=str(input())
print(s[::2])

Solution (Python):
print(''.join([s for s in input()[::2]]))

Solution (Python):
strInp = input()

strCnt = 1
rec = ""
for i in strInp:
  if strCnt % 2 != 0 :
    rec = rec + i
  strCnt += 1

print(rec)

Solution (Python):
s = input()
s = list(s)
s_cut = s[0::2]
ans = ""
for i in s_cut:
    ans += i
print(ans)

Solution (Python):
s=input()
c=""
for i in range(0,len(s),2):
    c=c+s[i]
print(c)

Solution (Python):
s = input()
output_char = list(range(0,len(s),2))

for i in output_char:
    print(s[i], end='')

Solution (Python):

s = input()
print(s[::2])

Solution (Python):
print(input()[::2])

Solution (Python):
print(input()[::2])

Solution (Python):
s = input()
print(s[::2])

Solution (Python):
print(input()[0::2])

Solution (Python):
print(input()[::2])

Solution (Python):
s = input()
t = ''
for i in range(len(s)):
  if i % 2 == 0:
    t += s[i]
print(t)

Solution (Python):
n=input()
word=""
for i in range(len(n)):
    if i%2==0:
        word+=n[i]
print(word)

Solution (Python):
n=input()

print(n[0::2])

Solution (Python):
s = input()

print(s[::2])

Solution (Python):
print(input()[::2])

Solution (Python):
print(input()[0::2])

Solution (Python):
s = input()
ans = ""
if len(s)%2 == 0:
    for i in range(len(s)//2):
        ans += s[2*i]
    print(ans)
else:
    for i in range(len(s)//2+1):
        ans += s[2*i]
    print(ans)

Solution (Python):
s = input()
new_s = []

for i in range(0, len(s), 2):
        new_s.append(s[i])

print(''.join(new_s))

Solution (Python):
s = input()
ans = ""
for i in range(0, len(s), 2):
    ans += s[i]
print(ans)

Solution (Python):
s = input()
ans = s[0]
for i in range(1,len(s)):
  if i % 2 == 0:
    ans += s[i]
print(ans)

Solution (Python):
print(input()[0::2])

Solution (Python):
s = input()
tmp = ''
for i,j in enumerate(s):
    if i%2 == 0:
        tmp += j
print(tmp)

Solution (Python):
print(input()[::2])

Solution (Python):
s = input()
n = len(s)
res = ''
for i in range(n)[0::2]:
  res = res + s[i]
print(res)

Solution (Python):
s = input()
ans = ''
for i in range(len(s)):
    if i % 2 == 0:
        ans += s[i]
print(ans)

Solution (Python):
s = str(input())
letters = list()
for i in range(len(s)):
    if i%2 == 0:
        letters.append(s[i])

print(''.join(letters))

Solution (Python):
s = input()

num = len(s)
ans = ""

for i in range(num):
    if i % 2 == 0:
        ans += s[i] 

print(ans)

Solution (Python):
s=input()
print(s[::2])

Solution (Python):
print(input()[::2])

Solution (Python):
s=list(input())
odd=[]
for i in range(len(s)):
    if i%2==0:
        odd.append(s[i])
print(''.join(odd))

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

str_odd = str_list[::2]

for s in str_odd:
    print(s, end = '')

Solution (Python):
s = input()
ans = ''
for i in range(1,len(s)+1):
    if i % 2 != 0:
        ans += s[i-1]
print(ans)

Solution (Python):
print(input()[::2])

Solution (Python):

import sys
INF = float("inf")


def solve(s: str):
    print(s[0::2])
    return


def main():

    def iterate_tokens():
        for line in sys.stdin:
            for word in line.split():
                yield word
    tokens = iterate_tokens()
    s = next(tokens)  
    solve(s)


if __name__ == '__main__':
    main()

Solution (Python):
s = input()
ans=''
while len(s)>2:
  ans+=s[0]
  s=s[2:]
print(ans+s[0])

Solution (Python):

s = input()
print(s[::2])

Solution (Python):
S = list(input())
print("".join(S[0::2]))

Solution (Python):
s = input()

ans = ''
for i in range(len(s)):
    if i % 2 == 0:
        ans += s[i]
        
print(ans)

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

for i in range(len(s)):
  if i%2==0:
    print(s[i],end='')

Solution (Python):
s = input()

for i in range(0, len(s), 2):
    print(s[i], end='')

Solution (Python):
s = input()
a = ''
for i in range(len(s)):
	if i % 2 == 0:
		a += s[i]
print(a)

Solution (Python):
print(input()[::2])

Solution (Python):
s = input()
print(s[::2])

Solution (Python):
print(input()[::2])

Solution (Python):

import sys
import copy
import collections
from bisect import bisect_left
from bisect import bisect_right
from collections import defaultdict
from heapq import heappop, heappush
import math
import itertools
 




 
def inputInt(): return int(input())
def inputMap(): return map(int, input().split())
def inputList(): return list(map(int, input().split()))
 
def main():
    s = list(input())
    ans = []
    for i, val in enumerate(s):
        if i == 0:
            ans.append(val)
            continue
        if i % 2 == 0:
            ans.append(val)
        
    print("".join(ans))
    
if __name__ == "__main__":
	main()

Solution (Python):
print(input()[::2])

Solution (Python):
S = input()
print(S[::2])

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


print(s[0::2])

Solution (Python):
s = input()
ans = ""
for i in range(0,len(s),2):
    ans += s[i]

print(ans)

Solution (Python):
s = input()
ans = ""
for i in range(0, len(s), 2):
  ans += s[i]
print(ans)

Solution (Python):
print(input()[::2])

Solution (Python):
s = input()
print(s[::2])

Solution (Python):
s = list(input())
s = [s[i] for i in range(len(s)) if i%2 == 0]
print(''.join(s))

Solution (Python):
s = list(input())
l = len(s)
ans = ''
i = 0

while True:
    if i >= l:
        break
    else:
        ans += s[i]
        i += 2

print(ans)

Solution (Python):
s = list(input())
ans = []
for i in range(0,len(s),2):
  ans.append(s[i])
print(''.join(ans))

Solution (Python):
s = list(input())
print("".join(s[::2]))

Solution (Python):
s = list(input())
num = len(s)
newl = []

for i in range(0,num,2):
    newl.append(s[i])
ans = "".join(newl)

print(ans)

Solution (Python):
s = list(input())
num = len(s)
newl = []

for i in range((num+1)//2):
    newl.append(s[2*i])
ans = "".join(newl)

print(ans)

Solution (Python):
s = input()
ans = ''
for i in range(len(s)):
    if i % 2 == 0:
        ans += s[i]
print(ans)

Solution (Python):
s = input()

l = []
for k in range(len(s)):
  if k % 2 == 0:
    l.append(s[k])
  else:
    pass

ans ="".join(l)
print(ans)

Solution (Python):
print(input()[::2])

Solution (Python):
print(input()[::2])

Solution (Python):
print(input()[::2])

Solution (Python):
print(input()[::2])

Solution (Python):
s = input()
ans = ""
for i in range(len(s)):
    if i % 2 == 0:
        ans += s[i]
print(ans)

Solution (Python):
S = str(input())
print(''.join(S[i] for i in range(len(S)) if i%2 == 0))

Solution (Python):
a = input()
b = ""
for i in range(0, len(a), 2):
    b += a[i]
print(b)

Solution (Python):
print(input()[::2])

Solution (Python):

from collections import defaultdict
from collections import deque
from heapq import heappush, heappop
import sys
import math
import bisect
import random
import itertools
sys.setrecursionlimit(10**5)
stdin = sys.stdin
def LI(): return list(map(int, stdin.readline().split()))
def LF(): return list(map(float, stdin.readline().split()))
def LI_(): return list(map(lambda x: int(x)-1, stdin.readline().split()))
def II(): return int(stdin.readline())
def IF(): return float(stdin.readline())
def LS(): return list(map(list, stdin.readline().split()))
def S(): return list(stdin.readline().rstrip())
def IR(n): return [II() for _ in range(n)]
def LIR(n): return [LI() for _ in range(n)]
def FR(n): return [IF() for _ in range(n)]
def LFR(n): return [LI() for _ in range(n)]
def LIR_(n): return [LI_() for _ in range(n)]
def SR(n): return [S() for _ in range(n)]
def LSR(n): return [LS() for _ in range(n)]
mod = 1000000007


def A():
    x, t = LI()
    print(max(0, x-t))
    return


def B():
    s = S()
    print("".join(s[::2]))
    return


def C():
    return


def D():
    return


if __name__ == '__main__':
    B()

Solution (Python):
s = input()
k=''
for i in range(len(s)):
    if(i%2==0):
        k+=s[i]
print(k)