
# slower version:

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


# optimized version of the same code:

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



# slower version:

import math

import string





def readints():

    return list(map(int, input().split()))





def nCr(n, r):

    return math.factorial(n)//(math.factorial(n-r)*math.factorial(r))





def has_duplicates2(seq):

    seen = []

    for item in seq:

        if not(item in seen):

            seen.append(item)

    return len(seq) != len(seen)





def divisor(n):

    divisor = []

    for i in range(1, n+1):

        if n % i == 0:

            divisor.append(i)

    return divisor





# coordinates

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

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



n = int(eval(input()))

a = readints()





def func(l):

    if len(l) == n:

        for i in range(len(l)):

            if l[i] % 2 == 0:

                return 1



        return 0

    return func(l+[(a[len(l)])])+func(l+[(a[len(l)]-1)])+func(l+[(a[len(l)]+1)])





print((func([])))


# optimized version of the same code:

import math

import string





def readints():

    return list(map(int, input().split()))





def nCr(n, r):

    return math.factorial(n)//(math.factorial(n-r)*math.factorial(r))





def has_duplicates2(seq):

    seen = []

    for item in seq:

        if not(item in seen):

            seen.append(item)

    return len(seq) != len(seen)





def divisor(n):

    divisor = []

    for i in range(1, n+1):

        if n % i == 0:

            divisor.append(i)

    return divisor





# coordinates

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

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



n = int(eval(input()))

a = readints()

sum = 1

for i in range(len(a)):

    if a[i] % 2 == 0:

        sum *= 2

    else:

        sum *= 1

print((3**len(a)-sum))

import math
import string


def readints():
    return list(map(int, input().split()))


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


def has_duplicates2(seq):
    seen = []
    for item in seq:
        if not (item in seen):
            seen.append(item)
    return len(seq) != len(seen)


def divisor(n):
    divisor = []
    for i in range(1, n + 1):
        if n % i == 0:
            divisor.append(i)
    return divisor


# coordinates
dx = [-1, -1, -1, 0, 0, 1, 1, 1]
dy = [-1, 0, 1, -1, 1, -1, 0, 1]
n = int(eval(input()))
a = readints()


def func(l):
    if len(l) == n:
        for i in range(len(l)):
            if l[i] % 2 == 0:
                return 1
        return 0
    return (
        func(l + [(a[len(l)])])
        + func(l + [(a[len(l)] - 1)])
        + func(l + [(a[len(l)] + 1)])
    )


print((func([])))

import math
import string


def readints():
    return list(map(int, input().split()))


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


def has_duplicates2(seq):
    seen = []
    for item in seq:
        if not (item in seen):
            seen.append(item)
    return len(seq) != len(seen)


def divisor(n):
    divisor = []
    for i in range(1, n + 1):
        if n % i == 0:
            divisor.append(i)
    return divisor


# coordinates
dx = [-1, -1, -1, 0, 0, 1, 1, 1]
dy = [-1, 0, 1, -1, 1, -1, 0, 1]
n = int(eval(input()))
a = readints()
sum = 1
for i in range(len(a)):
    if a[i] % 2 == 0:
        sum *= 2
    else:
        sum *= 1
print((3 ** len(a) - sum))

- - -def func(l): -    if len(l) == n: -        for i in range(len(l)): -            if l[i] % 2 == 0: -                return 1 -        return 0 -    return ( -        func(l + [(a[len(l)])]) -        + func(l + [(a[len(l)] - 1)]) -        + func(l + [(a[len(l)] + 1)]) -    ) - - -print((func([]))) +sum = 1 +for i in range(len(a)): +    if a[i] % 2 == 0: +        sum *= 2 +    else: +        sum *= 1 +print((3 ** len(a) - sum))