
# 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





def main():

    X, Y, Z, K = list(map(int, input().split(' ')))

    A = np.array(list(map(int, input().split(' '))))

    B = np.array(list(map(int, input().split(' '))))

    C = np.array(list(map(int, input().split(' '))))

    AB = np.array(np.meshgrid(A, B)).T.reshape(-1, 2).sum(axis=1)

    AB[::-1].sort()

    AB = AB[:min([K, X * Y])]

    ABC = np.array(np.meshgrid(AB, C)).T.reshape(-1, 2).sum(axis=1)

    ABC[::-1].sort()

    for ans in ABC[:K]:

        print(ans)





if __name__ == '__main__':

    main()

# optimized version of the same code:

from heapq import heappush, heappop

from collections import defaultdict





def main():

    X, Y, Z, K = list(map(int, input().split(' ')))

    A = list(map(int, input().split(' ')))

    B = list(map(int, input().split(' ')))

    C = list(map(int, input().split(' ')))

    A.sort(reverse=True)

    B.sort(reverse=True)

    C.sort(reverse=True)

    que = [(- A[0] - B[0] - C[0], 0, 0, 0)]  # multiply -1 to change min to max

    already_inserted = defaultdict(int)

    answer = list()

    for _ in range(K):

        q, i, j, k = heappop(que)

        answer.append(-q)

        if i + 1 < X:

            item_a = (- A[i + 1] - B[j] - C[k], i + 1, j, k)

            if already_inserted[item_a] == 0:

                heappush(que, item_a)

                already_inserted[item_a] = 1

        if j + 1 < Y:

            item_b = (- A[i] - B[j + 1] - C[k], i, j + 1, k)

            if already_inserted[item_b] == 0:

                heappush(que, item_b)

                already_inserted[item_b] = 1

        if k + 1 < Z:

            item_c = (- A[i] - B[j] - C[k + 1], i, j, k + 1)

            if already_inserted[item_c] == 0:

                heappush(que, item_c)

                already_inserted[item_c] = 1

    for ans in answer:

        print(ans)





if __name__ == '__main__':

    main()
import numpy as np


def main():
    X, Y, Z, K = list(map(int, input().split(" ")))
    A = np.array(list(map(int, input().split(" "))))
    B = np.array(list(map(int, input().split(" "))))
    C = np.array(list(map(int, input().split(" "))))
    AB = np.array(np.meshgrid(A, B)).T.reshape(-1, 2).sum(axis=1)
    AB[::-1].sort()
    AB = AB[: min([K, X * Y])]
    ABC = np.array(np.meshgrid(AB, C)).T.reshape(-1, 2).sum(axis=1)
    ABC[::-1].sort()
    for ans in ABC[:K]:
        print(ans)


if __name__ == "__main__":
    main()

from heapq import heappush, heappop
from collections import defaultdict


def main():
    X, Y, Z, K = list(map(int, input().split(" ")))
    A = list(map(int, input().split(" ")))
    B = list(map(int, input().split(" ")))
    C = list(map(int, input().split(" ")))
    A.sort(reverse=True)
    B.sort(reverse=True)
    C.sort(reverse=True)
    que = [(-A[0] - B[0] - C[0], 0, 0, 0)]  # multiply -1 to change min to max
    already_inserted = defaultdict(int)
    answer = list()
    for _ in range(K):
        q, i, j, k = heappop(que)
        answer.append(-q)
        if i + 1 < X:
            item_a = (-A[i + 1] - B[j] - C[k], i + 1, j, k)
            if already_inserted[item_a] == 0:
                heappush(que, item_a)
                already_inserted[item_a] = 1
        if j + 1 < Y:
            item_b = (-A[i] - B[j + 1] - C[k], i, j + 1, k)
            if already_inserted[item_b] == 0:
                heappush(que, item_b)
                already_inserted[item_b] = 1
        if k + 1 < Z:
            item_c = (-A[i] - B[j] - C[k + 1], i, j, k + 1)
            if already_inserted[item_c] == 0:
                heappush(que, item_c)
                already_inserted[item_c] = 1
    for ans in answer:
        print(ans)


if __name__ == "__main__":
    main()

-import numpy as np +from heapq import heappush, heappop +from collections import defaultdict -    A = np.array(list(map(int, input().split(" ")))) -    B = np.array(list(map(int, input().split(" ")))) -    C = np.array(list(map(int, input().split(" ")))) -    AB = np.array(np.meshgrid(A, B)).T.reshape(-1, 2).sum(axis=1) -    AB[::-1].sort() -    AB = AB[: min([K, X * Y])] -    ABC = np.array(np.meshgrid(AB, C)).T.reshape(-1, 2).sum(axis=1) -    ABC[::-1].sort() -    for ans in ABC[:K]: +    A = list(map(int, input().split(" "))) +    B = list(map(int, input().split(" "))) +    C = list(map(int, input().split(" "))) +    A.sort(reverse=True) +    B.sort(reverse=True) +    C.sort(reverse=True) +    que = [(-A[0] - B[0] - C[0], 0, 0, 0)]  # multiply -1 to change min to max +    already_inserted = defaultdict(int) +    answer = list() +    for _ in range(K): +        q, i, j, k = heappop(que) +        answer.append(-q) +        if i + 1 < X: +            item_a = (-A[i + 1] - B[j] - C[k], i + 1, j, k) +            if already_inserted[item_a] == 0: +                heappush(que, item_a) +                already_inserted[item_a] = 1 +        if j + 1 < Y: +            item_b = (-A[i] - B[j + 1] - C[k], i, j + 1, k) +            if already_inserted[item_b] == 0: +                heappush(que, item_b) +                already_inserted[item_b] = 1 +        if k + 1 < Z: +            item_c = (-A[i] - B[j] - C[k + 1], i, j, k + 1) +            if already_inserted[item_c] == 0: +                heappush(que, item_c) +                already_inserted[item_c] = 1 +    for ans in answer: