
# 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:

def main():

    import sys

    input = sys.stdin.readline

    sys.setrecursionlimit(10**7)

    from collections import Counter, deque

    #from collections import defaultdict

    from itertools import combinations, permutations, accumulate, groupby

    #from itertools import product

    from bisect import bisect_left,bisect_right

    import heapq

    from math import floor, ceil

    #from operator import itemgetter



    #inf = 10**17

    #mod = 10**9 + 7



    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()))

    ab = []

    for i in a:

        for j in b:

            ab.append(i+j)

    ab.sort(reverse=1)

    ab = ab[:k]

    abc = []

    for i in ab:

        for j in c:

            abc.append(i+j)

    abc.sort(reverse=1)

    for i in range(k):

        print((abc[i]))



if __name__ == '__main__':

    main()

# optimized version of the same code:

#xyzの全通り調べると間に合わない

#まず問題を分けよう

#先にxyだけ考えてみる

#xyの和をとってからそれとzの和をとるとき

#xyの和においてk番目以降の値を使うことは無い

#



def main():

    import sys

    input = sys.stdin.readline

    sys.setrecursionlimit(10**7)

    from collections import Counter, deque

    #from collections import defaultdict

    from itertools import combinations, permutations, accumulate, groupby

    #from itertools import product

    from bisect import bisect_left,bisect_right

    import heapq

    from math import floor, ceil

    #from operator import itemgetter



    #inf = 10**17

    #mod = 10**9 + 7



    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=1)

    b.sort(reverse=1)

    c.sort(reverse=1)

    abc = []

    for i in range(x):

        for j in range(y):

            if i*j>k:

                continue

            for t in range(z):

                if i*j*t>k:

                    continue

                abc.append(a[i]+b[j]+c[t])

    abc.sort(reverse=1)

    for i in range(k):

        print((abc[i]))



if __name__ == '__main__':

    main()
def main():
    import sys

    input = sys.stdin.readline
    sys.setrecursionlimit(10**7)
    from collections import Counter, deque

    # from collections import defaultdict
    from itertools import combinations, permutations, accumulate, groupby

    # from itertools import product
    from bisect import bisect_left, bisect_right
    import heapq
    from math import floor, ceil

    # from operator import itemgetter
    # inf = 10**17
    # mod = 10**9 + 7
    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()))
    ab = []
    for i in a:
        for j in b:
            ab.append(i + j)
    ab.sort(reverse=1)
    ab = ab[:k]
    abc = []
    for i in ab:
        for j in c:
            abc.append(i + j)
    abc.sort(reverse=1)
    for i in range(k):
        print((abc[i]))


if __name__ == "__main__":
    main()

# xyzの全通り調べると間に合わない
# まず問題を分けよう
# 先にxyだけ考えてみる
# xyの和をとってからそれとzの和をとるとき
# xyの和においてk番目以降の値を使うことは無い
#
def main():
    import sys

    input = sys.stdin.readline
    sys.setrecursionlimit(10**7)
    from collections import Counter, deque

    # from collections import defaultdict
    from itertools import combinations, permutations, accumulate, groupby

    # from itertools import product
    from bisect import bisect_left, bisect_right
    import heapq
    from math import floor, ceil

    # from operator import itemgetter
    # inf = 10**17
    # mod = 10**9 + 7
    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=1)
    b.sort(reverse=1)
    c.sort(reverse=1)
    abc = []
    for i in range(x):
        for j in range(y):
            if i * j > k:
                continue
            for t in range(z):
                if i * j * t > k:
                    continue
                abc.append(a[i] + b[j] + c[t])
    abc.sort(reverse=1)
    for i in range(k):
        print((abc[i]))


if __name__ == "__main__":
    main()

+# xyzの全通り調べると間に合わない +# まず問題を分けよう +# 先にxyだけ考えてみる +# xyの和をとってからそれとzの和をとるとき +# xyの和においてk番目以降の値を使うことは無い +# -    ab = [] -    for i in a: -        for j in b: -            ab.append(i + j) -    ab.sort(reverse=1) -    ab = ab[:k] +    a.sort(reverse=1) +    b.sort(reverse=1) +    c.sort(reverse=1) -    for i in ab: -        for j in c: -            abc.append(i + j) +    for i in range(x): +        for j in range(y): +            if i * j > k: +                continue +            for t in range(z): +                if i * j * t > k: +                    continue +                abc.append(a[i] + b[j] + c[t])