
# 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

from collections import deque

import numpy as np



def main():

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

    ab = np.array(sys.stdin.read().split(), dtype=np.int64).reshape(-1, 2)



    G = [[] for _ in range(n + 1)]

    for a, b in ab:

        G[a].append(b)

        G[b].append(a)

    

    parent = np.zeros(n + 1, dtype=np.int64)

    color = np.zeros(n + 1, dtype=np.int64) # color of the edge(parent[y], y)



    q = deque([1]) # root = 1

    while q:

        x = q.popleft()

        ng = color[x]

        c = 1

        for y in G[x]:

            if y == parent[x]:

                continue

            parent[y] = x

            if c == ng:

                c += 1

            color[y] = c

            q.append(y)

            c += 1



    print((np.amax(color)))



    for a, b in ab:

        if a == parent[b]:

            print((color[b]))

        else:

            print((color[a]))

            

if __name__ == '__main__':

    main()

# optimized version of the same code:

import sys

from collections import deque



def main():

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

    ab = list(map(int, sys.stdin.read().split()))

    ab = list(zip(ab, ab))



    G = [[] for _ in range(n + 1)]

    for a, b in ab:

        G[a].append(b)

        G[b].append(a)

    

    q = deque([1]) # root = 1

    parent = [None] * (n + 1)

    color = [0] * (n + 1) # color of the edge(parent[y], y)



    while q:

        x = q.popleft()

        ng = color[x]

        c = 1

        for y in G[x]:

            if y == parent[x]:

                continue

            parent[y] = x

            if c == ng:

                c += 1

            color[y] = c

            q.append(y)

            c += 1

            

    print((max(color)))



    for a, b in ab:

        if a == parent[b]:

            print((color[b]))

        else:

            print((color[a]))



if __name__ == '__main__':

    main()
import sys
from collections import deque
import numpy as np


def main():
    n = int(sys.stdin.readline().rstrip())
    ab = np.array(sys.stdin.read().split(), dtype=np.int64).reshape(-1, 2)
    G = [[] for _ in range(n + 1)]
    for a, b in ab:
        G[a].append(b)
        G[b].append(a)
    parent = np.zeros(n + 1, dtype=np.int64)
    color = np.zeros(n + 1, dtype=np.int64)  # color of the edge(parent[y], y)
    q = deque([1])  # root = 1
    while q:
        x = q.popleft()
        ng = color[x]
        c = 1
        for y in G[x]:
            if y == parent[x]:
                continue
            parent[y] = x
            if c == ng:
                c += 1
            color[y] = c
            q.append(y)
            c += 1
    print((np.amax(color)))
    for a, b in ab:
        if a == parent[b]:
            print((color[b]))
        else:
            print((color[a]))


if __name__ == "__main__":
    main()

import sys
from collections import deque


def main():
    n = int(sys.stdin.readline().rstrip())
    ab = list(map(int, sys.stdin.read().split()))
    ab = list(zip(ab, ab))
    G = [[] for _ in range(n + 1)]
    for a, b in ab:
        G[a].append(b)
        G[b].append(a)
    q = deque([1])  # root = 1
    parent = [None] * (n + 1)
    color = [0] * (n + 1)  # color of the edge(parent[y], y)
    while q:
        x = q.popleft()
        ng = color[x]
        c = 1
        for y in G[x]:
            if y == parent[x]:
                continue
            parent[y] = x
            if c == ng:
                c += 1
            color[y] = c
            q.append(y)
            c += 1
    print((max(color)))
    for a, b in ab:
        if a == parent[b]:
            print((color[b]))
        else:
            print((color[a]))


if __name__ == "__main__":
    main()

-import numpy as np -    ab = np.array(sys.stdin.read().split(), dtype=np.int64).reshape(-1, 2) +    ab = list(map(int, sys.stdin.read().split())) +    ab = list(zip(ab, ab)) -    parent = np.zeros(n + 1, dtype=np.int64) -    color = np.zeros(n + 1, dtype=np.int64)  # color of the edge(parent[y], y) +    parent = [None] * (n + 1) +    color = [0] * (n + 1)  # color of the edge(parent[y], y) -    print((np.amax(color))) +    print((max(color)))