
# 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

n = int(eval(input()))

a = list(map(int, input().split()))





def trial_division(n):

    factor = []

    tmp = int(math.sqrt(n)) + 1

    for _ in range(2,tmp):

        while n % 2 == 0:

            n //= 2

            factor.append(2)

    if not factor:

        return [n]

    else:

        factor.append(n)

        return factor





count = 0

for i in a:

    temp = trial_division(i)

    count += temp.count(2)



print(count)

# optimized version of the same code:

n = int(eval(input()))

a = list(map(int, input().split()))





def trial_division(n):

    #２で割った因数を格納するリスト

    factor = []

    #2で割れなくなった時点でストップ

    while n % 2 == 0:

        n //= 2    # ２で割った商を切り捨てて代入

        factor.append(2)

    #nが一度も２で割れなかったらそのまま返す

    if not factor:

        return [n]

    else:

        factor.append(n)

        return factor





count = 0

for i in a:

    temp = trial_division(i)

    count += temp.count(2)



print(count)
import math

n = int(eval(input()))
a = list(map(int, input().split()))


def trial_division(n):
    factor = []
    tmp = int(math.sqrt(n)) + 1
    for _ in range(2, tmp):
        while n % 2 == 0:
            n //= 2
            factor.append(2)
    if not factor:
        return [n]
    else:
        factor.append(n)
        return factor


count = 0
for i in a:
    temp = trial_division(i)
    count += temp.count(2)
print(count)

n = int(eval(input()))
a = list(map(int, input().split()))


def trial_division(n):
    # ２で割った因数を格納するリスト
    factor = []
    # 2で割れなくなった時点でストップ
    while n % 2 == 0:
        n //= 2  # ２で割った商を切り捨てて代入
        factor.append(2)
    # nが一度も２で割れなかったらそのまま返す
    if not factor:
        return [n]
    else:
        factor.append(n)
        return factor


count = 0
for i in a:
    temp = trial_division(i)
    count += temp.count(2)
print(count)

-import math - +    # ２で割った因数を格納するリスト -    tmp = int(math.sqrt(n)) + 1 -    for _ in range(2, tmp): -        while n % 2 == 0: -            n //= 2 -            factor.append(2) +    # 2で割れなくなった時点でストップ +    while n % 2 == 0: +        n //= 2  # ２で割った商を切り捨てて代入 +        factor.append(2) +    # nが一度も２で割れなかったらそのまま返す