
# 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:

N = int(eval(input()))

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

Q = int(eval(input()))

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



def binary_search(target_num, head, tail):

    idx = int((head+tail)/2)

    if target_num == S[idx]:

        return True

    elif target_num < S[idx]:

        if head == idx:

            return False

        return binary_search(target_num, head, idx-1)

    else:

        if tail == idx:

            return False

        return binary_search(target_num, idx+1, tail)





match_count = 0

for target_num in T:

    if binary_search(target_num, 0, len(S)-1):

        match_count += 1



print((str(match_count)))


# optimized version of the same code:

N = int(eval(input()))

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

Q = int(eval(input()))

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



def binary_search(target_num, head, tail):

    while head <= tail:

        idx = int((head+tail)/2)

        if target_num == S[idx]:

            return True

        elif target_num < S[idx]:

            tail = idx - 1

        else:

            head = idx + 1

    return False





match_count = 0

for target_num in T:

    if binary_search(target_num, 0, len(S)-1):

        match_count += 1



print((str(match_count)))

N = int(eval(input()))
S = list(map(int, input().split()))
Q = int(eval(input()))
T = list(map(int, input().split()))


def binary_search(target_num, head, tail):
    idx = int((head + tail) / 2)
    if target_num == S[idx]:
        return True
    elif target_num < S[idx]:
        if head == idx:
            return False
        return binary_search(target_num, head, idx - 1)
    else:
        if tail == idx:
            return False
        return binary_search(target_num, idx + 1, tail)


match_count = 0
for target_num in T:
    if binary_search(target_num, 0, len(S) - 1):
        match_count += 1
print((str(match_count)))

N = int(eval(input()))
S = list(map(int, input().split()))
Q = int(eval(input()))
T = list(map(int, input().split()))


def binary_search(target_num, head, tail):
    while head <= tail:
        idx = int((head + tail) / 2)
        if target_num == S[idx]:
            return True
        elif target_num < S[idx]:
            tail = idx - 1
        else:
            head = idx + 1
    return False


match_count = 0
for target_num in T:
    if binary_search(target_num, 0, len(S) - 1):
        match_count += 1
print((str(match_count)))

-    idx = int((head + tail) / 2) -    if target_num == S[idx]: -        return True -    elif target_num < S[idx]: -        if head == idx: -            return False -        return binary_search(target_num, head, idx - 1) -    else: -        if tail == idx: -            return False -        return binary_search(target_num, idx + 1, tail) +    while head <= tail: +        idx = int((head + tail) / 2) +        if target_num == S[idx]: +            return True +        elif target_num < S[idx]: +            tail = idx - 1 +        else: +            head = idx + 1 +    return False