
# 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:

S = eval(input())

N = len(S)

left = S[:int(N/2)]

right = S[int((N+2)/2):]

S_reversed = "".join(reversed(list(S)))

left_reversed = "".join(reversed(list(left)))

right_reversed = "".join(reversed(list(right)))



if S == S_reversed and left == left_reversed and right == right_reversed:

    print("Yes")

else:

    print("No")

# optimized version of the same code:

S = eval(input())

N = len(S)

left = S[:int(N/2)]

right = S[int((N+2)/2):]



if S == S[::-1] and left == left[::-1] and right == right[::-1]:

    print("Yes")

else:

    print("No")
S = eval(input())
N = len(S)
left = S[: int(N / 2)]
right = S[int((N + 2) / 2) :]
S_reversed = "".join(reversed(list(S)))
left_reversed = "".join(reversed(list(left)))
right_reversed = "".join(reversed(list(right)))
if S == S_reversed and left == left_reversed and right == right_reversed:
    print("Yes")
else:
    print("No")

S = eval(input())
N = len(S)
left = S[: int(N / 2)]
right = S[int((N + 2) / 2) :]
if S == S[::-1] and left == left[::-1] and right == right[::-1]:
    print("Yes")
else:
    print("No")

-S_reversed = "".join(reversed(list(S))) -left_reversed = "".join(reversed(list(left))) -right_reversed = "".join(reversed(list(right))) -if S == S_reversed and left == left_reversed and right == right_reversed: +if S == S[::-1] and left == left[::-1] and right == right[::-1]: