
# 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 sys

import numpy as np



x, y, z, k = map(int, sys.stdin.readline().split())

a, b, c = (np.array(sys.stdin.readline().split(), dtype=np.int64) for _ in range(3))



def main():

    res = np.sort(np.ravel(a[:, None] + b))[::-1]

    res = np.sort(np.ravel(c[:, None] + res[:min(k, x*y)]))[::-1]

    return res[:k]



if __name__ == '__main__':

    ans = main()

    print(*ans, sep='\n')


# optimized version of the same code:

import sys



x, y, z, K = map(int, sys.stdin.readline().split())

a, b, c = (sorted(map(int, sys.stdin.readline().split()), reverse=True) for _ in range(3))

def main():

    res = []

    for i in range(1, min(K, x) + 1):

        for j in range(1, min(K // i, y) + 1):

            for k in range(1, min(K // (i * j), z) + 1):

                res.append(a[i-1] + b[j-1] + c[k-1])



    return sorted(res, reverse=True)[:K]



if __name__ == '__main__':

    ans = main()

    print(*ans, sep='\n')

import sys
import numpy as np

x, y, z, k = map(int, sys.stdin.readline().split())
a, b, c = (np.array(sys.stdin.readline().split(), dtype=np.int64) for _ in range(3))


def main():
    res = np.sort(np.ravel(a[:, None] + b))[::-1]
    res = np.sort(np.ravel(c[:, None] + res[: min(k, x * y)]))[::-1]
    return res[:k]


if __name__ == "__main__":
    ans = main()
    print(*ans, sep="\n")

import sys

x, y, z, K = map(int, sys.stdin.readline().split())
a, b, c = (
    sorted(map(int, sys.stdin.readline().split()), reverse=True) for _ in range(3)
)


def main():
    res = []
    for i in range(1, min(K, x) + 1):
        for j in range(1, min(K // i, y) + 1):
            for k in range(1, min(K // (i * j), z) + 1):
                res.append(a[i - 1] + b[j - 1] + c[k - 1])
    return sorted(res, reverse=True)[:K]


if __name__ == "__main__":
    ans = main()
    print(*ans, sep="\n")

-import numpy as np -x, y, z, k = map(int, sys.stdin.readline().split()) -a, b, c = (np.array(sys.stdin.readline().split(), dtype=np.int64) for _ in range(3)) +x, y, z, K = map(int, sys.stdin.readline().split()) +a, b, c = ( +    sorted(map(int, sys.stdin.readline().split()), reverse=True) for _ in range(3) +) -    res = np.sort(np.ravel(a[:, None] + b))[::-1] -    res = np.sort(np.ravel(c[:, None] + res[: min(k, x * y)]))[::-1] -    return res[:k] +    res = [] +    for i in range(1, min(K, x) + 1): +        for j in range(1, min(K // i, y) + 1): +            for k in range(1, min(K // (i * j), z) + 1): +                res.append(a[i - 1] + b[j - 1] + c[k - 1]) +    return sorted(res, reverse=True)[:K]