
# 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





def main():

    h, w = list(map(int, sys.stdin.buffer.readline().split()))

    n = int(sys.stdin.buffer.readline())

    a = list(map(int, sys.stdin.buffer.readline().split()))

    ans = np.zeros(w*h, np.int64)

    now = 0

    for i, x in enumerate(a):

        for j in range(x):

            ans[now + j] = i+1

        now += x



    ans = ans.reshape(h, w)

    for i in range(h):

        if i % 2:

            print((*ans[i, ::-1]))

        else:

            print((*ans[i]))





if __name__ == "__main__":

    main()


# optimized version of the same code:

import sys





def main():

    h, w = list(map(int, sys.stdin.buffer.readline().split()))

    n = int(sys.stdin.buffer.readline())

    a = list(map(int, sys.stdin.buffer.readline().split()))

    ans = [0]*(w*h)

    now = 0

    for i, x in enumerate(a):

        for j in range(x):

            ans[now + j] = i+1

        now += x



    for i in range(h):

        if i % 2:

            print((*reversed(ans[i*w:(i+1)*w])))

        else:

            print((*ans[i*w:(i+1)*w]))





if __name__ == "__main__":

    main()

import sys
import numpy as np


def main():
    h, w = list(map(int, sys.stdin.buffer.readline().split()))
    n = int(sys.stdin.buffer.readline())
    a = list(map(int, sys.stdin.buffer.readline().split()))
    ans = np.zeros(w * h, np.int64)
    now = 0
    for i, x in enumerate(a):
        for j in range(x):
            ans[now + j] = i + 1
        now += x
    ans = ans.reshape(h, w)
    for i in range(h):
        if i % 2:
            print((*ans[i, ::-1]))
        else:
            print((*ans[i]))


if __name__ == "__main__":
    main()

import sys


def main():
    h, w = list(map(int, sys.stdin.buffer.readline().split()))
    n = int(sys.stdin.buffer.readline())
    a = list(map(int, sys.stdin.buffer.readline().split()))
    ans = [0] * (w * h)
    now = 0
    for i, x in enumerate(a):
        for j in range(x):
            ans[now + j] = i + 1
        now += x
    for i in range(h):
        if i % 2:
            print((*reversed(ans[i * w : (i + 1) * w])))
        else:
            print((*ans[i * w : (i + 1) * w]))


if __name__ == "__main__":
    main()

-import numpy as np -    ans = np.zeros(w * h, np.int64) +    ans = [0] * (w * h) -    ans = ans.reshape(h, w) -            print((*ans[i, ::-1])) +            print((*reversed(ans[i * w : (i + 1) * w]))) -            print((*ans[i])) +            print((*ans[i * w : (i + 1) * w]))