
# 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 numpy as np

cookies = np.array([int(x) for x in input().split()])



if any(cookies%2):

  ans = 0

elif cookies[0] == cookies[1] == cookies[2]:

  ans = -1

else:

  ans = 0

  while True:

    if not any(cookies%2):

      cookies = cookies//2

      ans += 1

      continue

    if all(cookies%2):

      ans += 1

    break

print(ans)

# optimized version of the same code:

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

if a == b == c and a%2 == 0:

  print((-1))

elif a%2 or b%2 or c%2:

  print((0))

else:

  ans = 0

  while a%2 == b%2 == c%2 == 0:

    a, b, c = (b+c)//2, (a+c)//2, (a+b)//2

    ans += 1

  print(ans)
import numpy as np

cookies = np.array([int(x) for x in input().split()])
if any(cookies % 2):
    ans = 0
elif cookies[0] == cookies[1] == cookies[2]:
    ans = -1
else:
    ans = 0
    while True:
        if not any(cookies % 2):
            cookies = cookies // 2
            ans += 1
            continue
        if all(cookies % 2):
            ans += 1
        break
print(ans)

a, b, c = list(map(int, input().split()))
if a == b == c and a % 2 == 0:
    print((-1))
elif a % 2 or b % 2 or c % 2:
    print((0))
else:
    ans = 0
    while a % 2 == b % 2 == c % 2 == 0:
        a, b, c = (b + c) // 2, (a + c) // 2, (a + b) // 2
        ans += 1
    print(ans)

-import numpy as np - -cookies = np.array([int(x) for x in input().split()]) -if any(cookies % 2): -    ans = 0 -elif cookies[0] == cookies[1] == cookies[2]: -    ans = -1 +a, b, c = list(map(int, input().split())) +if a == b == c and a % 2 == 0: +    print((-1)) +elif a % 2 or b % 2 or c % 2: +    print((0)) -    while True: -        if not any(cookies % 2): -            cookies = cookies // 2 -            ans += 1 -            continue -        if all(cookies % 2): -            ans += 1 -        break -print(ans) +    while a % 2 == b % 2 == c % 2 == 0: +        a, b, c = (b + c) // 2, (a + c) // 2, (a + b) // 2 +        ans += 1 +    print(ans)